Patent Publication Number: US-8121985-B2

Title: Delta versioning for learning objects

Description:
TECHNICAL FIELD 
     This disclosure relates to learning systems and, more specifically, to systems, methods, and software involving delta versioning for learning objects. 
     BACKGROUND 
     Today, an enterprise&#39;s survival in local or global markets at least partially depends on the knowledge and competencies of its employees, which may easily be considered a competitive factor for the enterprises (or other organizations). Shorter product life cycles and the speed with which the enterprise can react to changing market requirements are often important factors in competition and ones that underline the importance of being able to convey information on products and services to employees as swiftly as possible. Moreover, enterprise globalization and the resulting international competitive pressure are making rapid global knowledge transfer even more significant. Thus, enterprises are often faced with the challenge of lifelong learning to train a (perhaps globally) distributed workforce, update partners and suppliers about new products and developments, educate apprentices or new hires, or set up new markets. In other words, efficient and targeted learning is a challenge that learners, employees, and employers are equally faced with. But traditional classroom training typically ties up time and resources, takes employees away from their day-to-day tasks, and drives up expenses. 
     Electronic learning systems provide users with the ability to access course content directly from their computers, without the need for intermediaries such as teachers, tutors, and the like. Such systems have proven attractive for this reason (and perhaps others) and may include a master repository that stores existing versions of learning objects. Typically, each time a new version of an object is created, contained files are stored again even if the individual files have not changed. This often requires a large amount of storage required on the repository hardware and may also considerably slow down the storing of the objects. 
     SUMMARY 
     A method for versioning learning objects comprises identifying learning content, which includes a plurality of learning objects, for storage in a content repository. Each learning object comprises or contains at least one content file. The method then includes comparing first version information of a first of the content files to versioning information obtained from an object version file identifying a prior version of the particular learning object. In response to at least a portion of the first version information of the first content file matching a corresponding portion of the versioning information stored in the object version file, a pointer to a corresponding content file in the prior version of the learning object is stored in a new object version file. 
     In another embodiment, a method for managing versioned content files includes receiving a request for learning content from a user, with the learning content associated with a plurality of learning objects, each learning object comprising at least one content file, and at least a subset of the learning objects files being reusable for other learning content. The method further includes identifying a versioning object from a content repository based, at least in part, on a first learning object in the requested request. Next, a mapping table is generated from the versioning object, the table comprising a plurality of mapping entries, with each entry indicating a relative path for one of the plurality of content files. The method includes comparing a first content file in the first learning object to the mapping table. If a mapping entry is found for a particular requested content file, then the referenced file is collected using the relative path; but if no mapping is found for the particular requested content file, then the referenced file is collected from the versioning object. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating an example learning environment according to one embodiment of the present disclosure; 
         FIG. 2  illustrates an example architecture of a learning management system implemented within the learning environment of  FIG. 1 ; 
         FIG. 3  illustrates an example content aggregation model in the learning management system; 
         FIG. 4  is an example of one possible ontology of knowledge types used in the learning management system; 
         FIGS. 5A-B  are flow diagrams illustrating example methods for developing content for use by at least a portion of the learning environment of  FIG. 1 ; 
         FIGS. 6A-D  illustrate an interface of an example check-in wizard implementing certain versioning techniques or process; 
         FIGS. 7A-B  illustrate an example graphical user interface for viewing versions of learning objects and the respective content files; and 
         FIG. 8  is a flow diagram illustrating an example method for delta versioning learning objects used by at least a portion of the learning environment of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an example environment for a learning management system  140  that may deliver a blended learning solution of learning methods used in traditional classroom training, web-based training, and virtual classrooms. At a high level, such applications  140  provide convenient information on the learner  104 &#39;s virtual workplace and at least partially control the learning process itself. The system proposes learning units based on the learner  104 &#39;s personal data, tracks progress through courses and coordinates the personalized learning experience. In addition, learning management system  140  encompasses the administrative side of the learning platform, where a training administrator  105  structures and updates the offering and distributes it among the target groups. Moreover, the course offering is usually not restricted to internally hosted content. The learning management system  140  often offers robust reporting capabilities, including ad hoc reporting and business intelligence. These capabilities may provide in-depth analysis of the entire business or organization, thereby enabling better decision making. Moreover, while implementing certain versioning techniques, learning management system  140  significantly improves the time and storage required for creating versions of particular learning objects, while maintaining the basic structure of the original format helping to ensure compatibility with other systems. More specifically, support for accessing delta versioned files may be transparent to the learner  104  via the existing client, such that applications reading the content can remain unchanged. Also the lookup for a referenced file is often fast and therefore the read performance may not be affected in any significant way. 
     Learning management system  140  also typically helps improve the quality of training and cut costs by reducing the travel and administrative costs associated with classroom training while delivering a consistent learning offering. Training administrators  105  may customize teaching scenarios by using web services to integrate external content, functions, and services into the learning platform from a remote or third party content provider  108 . The training administrator  105  can administer internal and external participants (or learners  104 ) and enroll them for courses to be delivered via any number of techniques. Training management supports the respective organization, entity, or learner  104  in the day-to-day activities associated with course bookings. Booking activities can be performed by the training administrator in training management on an individual or group participant basis. For example, training administrator  105  can often request, execute, or otherwise manage the following activities in a dynamic participation menu presented in learning management system  140 : i) prebook: if participants are interested in taking certain classroom courses or virtual classroom sessions, but there are no suitable dates scheduled, learners  104  can be prebooked for the course types. Prebooking data can be used to support a demand planning process; ii) book: individual or group learners  104  (for example, companies, departments, roles, or other organizational units) can be enrolled for courses that can be delivered using many technologies; iii) rebook: learners  104  can book a course on an earlier or later date than originally booked; iv) replace: learners  104  can be swapped; and v) cancel: course bookings can be canceled, for example, if the learners  104  cannot attend. 
     Environment  100  is typically a distributed client/server system that spans one or more networks such as external network  112  or internal network  114 . In such embodiments, data may be communicated or stored in an encrypted format such as, for example, using the RSA, WEP, or DES encryption algorithms. But environment  100  may be in a dedicated enterprise environment—across a local area network or subnet—or any other suitable environment without departing from the scope of this disclosure. Indeed, while generally described or referenced in terms of an enterprise, the components and techniques may be implemented in any suitable environment, organization, entity, and such. Turning to the illustrated embodiment, environment  100  includes or is communicably coupled with server  102 , one or more learners  104  or other users on clients, and network  112 . In this embodiment, environment  100  is also communicably coupled with external content provider  108 . 
     Server  102  comprises an electronic computing device operable to receive, transmit, process and store data associated with environment  100 . Generally,  FIG. 1  provides merely one example of computers that may be used with the disclosure. Each computer is generally intended to encompass any suitable processing device. For example, although  FIG. 1  illustrates one server  102  that may be used with the disclosure, environment  100  can be implemented using computers other than servers, as well as a server pool. Indeed, server  102  may be any computer or processing device such as, for example, a blade server, general-purpose personal computer (PC), Macintosh, workstation, Unix-based computer, or any other suitable device. In other words, the present disclosure contemplates computers other than general purpose computers as well as computers without conventional operating systems. Server  102  may be adapted to execute any operating system including Linux, UNIX, Windows Server, or any other suitable operating system. According to one embodiment, server  102  may also include or be communicably coupled with a web server and/or a mail server. Server  102  may also be communicably coupled with a remote repository over a portion of network  112 . While not illustrated, the repository may be any intra-enterprise, inter-enterprise, regional, nationwide, or other electronic storage facility, data processing center, or archive that allows for one or a plurality of clients (as well as servers  102 ) to dynamically store data elements, which may include any business, enterprise, application or other transaction data. For example, the repository may be a central database communicably coupled with one or more servers  102  and clients via a virtual private network (VPN), SSH (Secure Shell) tunnel, or other secure network connection. This repository may be physically or logically located at any appropriate location including in one of the example enterprises or off-shore, so long as it remains operable to store information associated with environment  100  and communicate such data to at least a subset of plurality of the clients (perhaps via server  102 ). 
     As a possible supplement to or as a portion of this repository, server  102  normally includes some form of local memory. The memory may include any memory or database module and may take the form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component. For example, the memory may store or reference a large volume of information relevant to the planning, management, and follow-up of courses or other content. This example data includes information on i) course details, such as catalog information, dates, prices, capacity, time schedules, assignment of course content, and completion times; ii) personnel resources, such as trainers who are qualified to hold courses; iii) room details, such as addresses, capacity, and equipment; and iv) participant data for internal and external participants. The memory may also include any other appropriate data such as VPN applications or services, firewall policies, a security or access log, print or other reporting files, HTML files or templates, data classes or object interfaces, child software applications or sub-systems, and others. In some embodiments, the memory may store information as one or more tables in a relational database described in terms of SQL statements or scripts. In another embodiment, the memory may store information as various data structures in text files, eXtensible Markup Language (XML) documents, Virtual Storage Access Method (VSAM) files, flat files, Btrieve files, comma-separated-value (CSV) files, internal variables, or one or more libraries. But any stored information may comprise one table or file or a plurality of tables or files stored on one computer or across a plurality of computers in any appropriate format. Indeed, some or all of the learning or content data may be local or remote without departing from the scope of this disclosure and store any type of appropriate data. 
     Server  102  also includes one or more processors. Each processor executes instructions and manipulates data to perform the operations of server  102  such as, for example, a central processing unit (CPU), a blade, an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). Although this disclosure typically discusses computers in terms of a single processor, multiple processors may be used according to particular needs and reference to one processor is meant to include multiple processors where applicable. In the illustrated embodiment, the processor executes enterprise resource planning (ERP) solution  135 , thereby providing organizations with the strategic insight, ability to differentiate, increased productivity, and flexibility they need to succeed. With software such as ERP solution  135 , the implementing entity may automate end-to-end processes and extend those processes beyond the particular organization to the entire system by incorporating customers, partners, suppliers, or other entities. For example, ERP solution  135  may include or implement easy-to-use self-services and role-based access to information and services for certain users, thereby possibly boosting productivity and efficiency. In another example, ERP solution  135  may include or implement analytics that enable the particular entity or user to evaluate performance and analyze operations, workforce, and financials on an entity and individual level for strategic and operational insight. ERP solution  135  may further include or implement i) financials to control corporate finance functions while providing support for compliance to rigorous regulatory mandates; ii) operations to support end-to-end logistics for complete business cycles and capabilities that improve product quality, costs, and time to market; and/or iii) corporate services to optimize both centralized and decentralized services for managing real estate, project portfolios, business travel, environment, health and safety, and quality. In the illustrated embodiment, ERP solution  135  also includes or implements some form of human capital management (in this case, learning) to maximize the profitability or other measurable potential of the users, with support for talent management, workforce deployment, and workforce process management. In certain cases, ERP solution  135  may be a composite application that includes, execute, or otherwise implement some or all of the foregoing aspects, which include learning management system  140  as illustrated. 
     As briefly described above, learning management system  140  is any software operable to provide a comprehensive enterprise learning platform capable of managing and integrating business and learning processes and supporting all methods of learning, not restricted to e-learning or classroom training. As described in more detail in  FIG. 2 , learning management system  140  is often fully integrated with ERP solution  135  and includes an intuitive learning portal and a powerful training and learning management system, as well as content authoring, structuring, and management capabilities. Learning management system  140  offers back-office functionality for competency management and comprehensive assessment for performance management, and offers strong analytical capabilities, including support for ad hoc reporting. The solution uses a comprehensive learning approach to deliver knowledge to all stakeholders, and tailors learning paths to an individual&#39;s educational needs and personal learning style. Interactive learning units can be created with a training simulation tool that is also available. 
     Regardless of the particular implementation, “software” may include software, firmware, wired or programmed hardware, or any combination thereof as appropriate. 
     Indeed, ERP solution  135  may be written or described in any appropriate computer language including C, C++, Java, J#, Visual Basic, assembler, Perl, any suitable version of 4GL, as well as others. For example, returning to the above described composite application, the composite application portions may be implemented as Enterprise Java Beans (EJBs) or the design-time components may have the ability to generate run-time implementations into different platforms, such as J2EE (Java 2 Platform, Enterprise Edition), ABAP (Advanced Business Application Programming) objects, or Microsoft&#39;s .NET. It will be understood that while ERP solution  135  is illustrated in  FIG. 1  as including one sub-module learning management system  140 , ERP solution  135  may include numerous other sub-modules or may instead be a single multi-tasked module that implements the various features and functionality through various objects, methods, or other processes. Further, while illustrated as internal to server  102 , one or more processes associated with ERP solution  135  may be stored, referenced, or executed remotely. For example, a portion of ERP solution  135  may be a web service that is remotely called, while another portion of ERP solution  135  may be an interface object bundled for processing at the remote client. Moreover, ERP solution  135  and/or learning management system  140  may be a child or sub-module of another software module or enterprise application (not illustrated) without departing from the scope of this disclosure. 
     Server  102  may also include an interface for communicating with other computer systems, such as the clients, over networks, such as  112  or  114 , in a client-server or other distributed environment. In certain embodiments, server  102  receives data from internal or external senders through the interface for storage in the memory and/or processing by the processor. Generally, the interface comprises logic encoded in software and/or hardware in a suitable combination and operable to communicate with networks  112  or  114 . More specifically, the interface may comprise software supporting one or more communications protocols associated with communications network  112  or hardware operable to communicate physical signals. 
     Network  112  facilitates wireless or wireline communication between computer server  102  and any other local or remote computers, such as clients. Network  112 , as well as network  114 , facilitates wireless or wireline communication between computer server  102  and any other local or remote computer, such as local or remote clients or a remote content provider  108 . While the following is a description of network  112 , the description may also apply to network  114 , where appropriate. For example, while illustrated as separate networks, network  112  and network  114  may be a continuous network logically divided into various sub-nets or virtual networks without departing from the scope of this disclosure. In some embodiments, network  112  includes access points that are responsible for brokering exchange of information between the clients. As discussed above, access points may comprise conventional access points, wireless security gateways, bridges, wireless switches, sensors, or any other suitable device operable to receive and/or transmit wireless signals. In other words, network  112  encompasses any internal or external network, networks, sub-network, or combination thereof operable to facilitate communications between various computing components in system  100 . Network  112  may communicate, for example, Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, and other suitable information between network addresses. Network  112  may include one or more local area networks (LANs), radio access networks (RANs), metropolitan area networks (MANs), wide area networks (WANs), all or a portion of the global computer network known as the Internet, and/or any other communication system or systems at one or more locations. Turning to network  114 , as illustrated, it may be all or a portion of an enterprise or secured network. In another example, network  114  may be a VPN between server  102  and a particular client across wireline or wireless links. In certain embodiments, network  114  may be a secure network associated with the enterprise and certain local or remote clients. 
     Each client is any computing device operable to connect or communicate with server  102  or other portions of the network using any communication link. At a high level, each client includes or executes at least GUI  116  and comprises an electronic computing device operable to receive, transmit, process and store any appropriate data associated with environment  100 . It will be understood that there may be any number of clients communicably coupled to server  102 . Further, “client” and “learner,” “administrator,” “developer,” and “user” may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, for ease of illustration, each client is described in terms of being used by one user. But this disclosure contemplates that many users may use one computer or that one user may use multiple computers. As used in this disclosure, the client is intended to encompass a personal computer, touch screen terminal, workstation, network computer, kiosk, wireless data port, smart phone, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device or computer. For example, the client may be a PDA operable to wirelessly connect with external or unsecured network. In another example, the client may comprise a laptop that includes an input device, such as a keypad, touch screen, mouse, or other device that can accept information, and an output device that conveys information associated with the operation of server  102  or other clients, including digital data, visual information, or GUI  116 . Both the input device and output device may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to users of the clients through the display, namely the client portion of GUI or application interface  116 . 
     GUI  116  comprises a graphical user interface operable to allow the user of the client to interface with at least a portion of environment  100  for any suitable purpose, such as viewing application or other transaction data. Generally, GUI  116  provides the particular user with an efficient and user-friendly presentation of data provided by or communicated within environment  100 . As shown in later FIGs, GUI  116  may comprise a plurality of customizable frames or views having interactive fields, pull-down lists, and buttons operated by the user. GUI  116  may be a learning interface allowing the user or learner  104  to search a course catalog, book and cancel course participation, and support individual course planning (e.g., by determining qualification deficits and displaying a learner&#39;s completed, started, and planned training activities). Learner  104  also may access and work through web based courses using the learning interface. The learning interface may be used to start a course, reenter a course, exit a course, and take tests. The learning interface also provides messages, notes, and special course offerings to the learner  104 . GUI  116  may also be a course editor allowing the content developer to create the structure for the course content, which may be associated with certain metadata. The metadata may be interpreted by a content player of learning management system  140  (described below) to present a course to learner  104  according to a learning strategy selected at run time. In particular, the course editor may enable the author or content developer  106  to classify and describe structural elements, assign attributes to structural elements, assign relations between structural elements, and build a subject-taxonomic course structure. The course editor generates the structure of the course and may include a menu bar, a button bar, a course overview, a dialog box, and work space. The menu bar may include various drop-down menus, such as, for example, file, edit, tools, options, and help. The drop-down menus may include functions, such as create a new course, open an existing course, edit a course, or save a course. The button bar may include a number of buttons. The buttons may be shortcuts to functions in the drop down menus that are used frequently and that activate tools and functions for use with the course editor. The remaining portions of the example course editor interface may be divided in to three primary sections or windows: a course overview, a dialog box, and a workspace. Each of the sections may be provided with horizontal or vertical scroll bars or other means allowing the windows to be sized to fit on different displays while providing access to elements that may not appear in the window. 
     GUI  116  may also present a plurality of portals or dashboards. For example, GUI  116  may display a portal that allows users to view, create, and manage historical and real-time reports including role-based reporting and such. Generally, historical reports provide critical information on what has happened including static or canned reports that require no input from the user and dynamic reports that quickly gather run-time information to generate the report. Of course, reports may be in any appropriate output format including PDF, HTML, and printable text. Real-time dashboards often provide table and graph information on the current state of the data, which may be supplemented by presentation elements  140 . GUI  116  is often configurable, supporting a combination of tables and graphs (bar, line, pie, status dials, etc.), and is able to build real-time dashboards, where presentation elements  140  (as well the displayed application or transaction data) may be relocated, resized, and such. It should be understood that the term graphical user interface may be used in the singular or in the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Indeed, reference to GUI  116  may indicate a reference to the front-end or other component of learning management system  140 , as well as the particular interface or learning portal accessible via the client, as appropriate, without departing from the scope of this disclosure. In short, GUI  116  contemplates any graphical user interface, such as a generic web browser or touch screen, that processes information in environment  100  and efficiently presents the results to the user. Server  102  can accept data from the client via the web browser (e.g., Microsoft Internet Explorer or Netscape Navigator) and return the appropriate HTML or XML responses to the browser using network  112  or  114 , such as those illustrated in subsequent FIGs. 
       FIG. 2  illustrates one example implementation of learning management system (LMS)  140 . In the illustrated embodiment, LMS  140  comprises four example components, namely i) a management system core  202 , which controls learning processes and manages and handles the administrative side of training; ii) a learning portal  204 , which is the learner&#39;s springboard into the learning environment, which allows him to access the course offering and information on personal learning data and learning activities; iii) an authoring environment  210 , where learning content and tests are designed and structured; and iv) a content management system  220 , where learning content is stored and managed. Generally, LMS  140  is aimed at learners  104 , trainers  105 , course authors  106  and instructional designers, administrators, and managers. 
     Learners  104  log on to their personalized learning portal  204  from any suitable client via GUI  116 . The learning portal  204  is the user&#39;s personalized point of access to the learning-related functions. Generally, learning portal  204  presents details of the complete education and training offering, such as traditional classroom training, e-learning courses (such as virtual classroom sessions or web-based training), or extensive curricula. Self-service applications enable learners  104  to enroll themselves for courses, prebook for classroom courses, and cancel bookings for delivery methods, as well as start self-paced learning units directly. If learner  104  wants to continue learning offline, he can often download the courses onto the client and synchronize the learning progress later. The learning portal  204  may be seamlessly integrated in an enterprise portal, where learner  104  is provided with access to a wide range of functions via one system. Such an enterprise portal may be the learner&#39;s single point of entry and may integrate a large number of role-based functions, which are presented to the user in a clear, intuitive structure. The learning portal  204  often gives learner  104  access to functions such as, for example, search for courses using i) find functions: finding courses in the course catalog that have keywords in the course title or description; and ii) extended search functions: using the attributes appended to courses, such as target group, prerequisites, qualifications imparted, or delivery method. Additional functions may include self-service applications for booking courses and canceling bookings, messages and notes, course appraisals, and special (or personalized) course offering including courses prescribed for the learner  104  on the basis of his or her role in the enterprise or the wishes of the respective supervisor or trainer and qualification deficits of learner  104  that can be reduced or eliminated by participating in the relevant courses. The learning portal  204  may also provide a view of current and planned training activities, as well as access to courses booked, including: i) starting a course; ii) reentering an interrupted course; iii) downloading a course and continuing learning offline; iv) going online again with a downloaded course and synchronizing the learning progress; v) exiting a course; and vi) taking a test. 
     On the basis of the information the learning management system  140  has about learner  104 , the learning management system core  202  proposes learning units for the learner  104 , monitors the learner&#39;s progress, and coordinates the learner&#39;s personal learning process. In addition, the learning management system core  202  is often responsible for managing and handling the administrative processes. Targeted knowledge transfer may use precise matching of the learning objectives and qualifications of a learning unit with the learner&#39;s level of knowledge. For example, at the start of a course, the management system core  202  may compare learning objectives already attained by the respective learner  104  with the learning objectives of the course. On the basis of this, core  202  determines the learner&#39;s current level and the required content and scope of the course. The resulting course is then presented to the learner  104  via a content player  208 . 
     The content player  208  is a virtual teacher that tailors learning content to the needs of the individual learner  104  and helps him navigate through the course; content player  208  then presents the learning course to the learner  104 . In certain embodiments, the content player  208  is a Java application that is deployed on a Java runtime environment, such as J2EE. In this case, it is typically linked with other systems (such as, a web application server, ERP solution  135 , and content  220 ) via the Java Connector. The individual course navigation may be set up at runtime on the basis of the learning strategy stored in the learner account. Using the didactical strategies, content player  208  helps ensure that the course is dynamically adapted to the individual learning situation and the preferences expressed by learner  104 . At this point, the content player  208  then calculates dynamically adjusted learning paths and presents these to the learner  104 —perhaps graphically—to facilitate orientation within a complex subject area. The learner  104  can resume working on an interrupted course at any time. At this point, the content player  208  guides the learner  104  to the spot at which training was interrupted. 
     Offline learning player  206  generally enables learners  104  to download network or other web-based courses via the learning portal  204  and play them locally. Locally stored courses are listed in the course list with an icon indicating the status of each course. The offline player  206  may guide the learner  104  through the course according to the preferred learning strategy. It may also dynamically adjust the number and sequence of learning objects to the learner&#39;s individual learning pattern. If the learner  104  interrupts a course, the offline player  206  reenters the course at the point of interruption the next time. The learner  104  can, at any point in time, resynchronize his offline learning progress with the learning portal  204  and either continue learning online or set the course to a completed status. 
     LMS core  202  may also include or invoke training management that would be an administrative side of LMS  140 . This typically includes course planning and execution, booking and cancellation of course participation, and follow-up processing, including cost settlement. In training management, the training administrator  105  creates the course offering and can, for example, define training measures for individual learners  104  and groups of learners  104 . The training administrator  105  creates the course catalog in training management and makes it available (partially or completely) to learners  104  in the learning portal  204  for reference and enrollment purposes. The training administrator  105  can typically administer internal and external participants and enroll them for courses to be delivered using various technologies and techniques. Training management supports numerous business processes involved in the organization, management, and handling of training. Training management can be configured to meet the requirements, work processes, and delivery methods common in the enterprise. Training measures are usually flexibly structured and may include briefings, seminars, workshops, virtual classroom sessions, web-based trainings, external web-based trainings, static web courses, or curricula. Training management includes functions to efficiently create the course offerings. Using course groups to categorize topics by subject area enables flexible structuring of the course catalog. For example, when training administrator  105  creates a new subject area represented by a course group, he can decide whether it should be accessible to learners  104  in the learning portal  202 . 
     Reporting functions  214  in training management enable managers to keep track of learners&#39; learning activities and the associated costs at all times. Supervisors or managers can monitor and steer the learning processes of their employees. They can be notified when their employees request participation or cancellation in courses and can approve or reject these requests. LMS  140  may provide the training manager with extensive support for the planning, organization, and controlling of corporate education and training. Trainers need to have up-to-the-minute, reliable information about their course schedules. There is a wide range of reporting options available in training management to enable the trainer to keep track of participants, rooms, course locations, and so on. 
     Authoring environment  210  contains tools and wizards that content developers  106  and instructional designers can use to create or import external course content. Content developers  106  often incorporate the roles of instructional designer and subject matter expert. For example, the instructional designer, as the methodological-didactical expert, may be responsible for designing course structures in line with specific guidelines. The example subject matter expert may be responsible for creating instructional content according to the specifications of the instructional designer. External authoring tools can be launched directly via authoring environment  210  to create learning content that can be integrated into learning objects and combined to create complete courses (learning nets). Attributes may be appended to content, thereby allowing learners  104  to structure learning content more flexibly depending on the learning strategy they prefer. Customizable and flexible views allow subject matter experts and instructional designers to configure and personalize the authoring environment  210 . To create the HTML pages for the content, the user can easily and seamlessly integrate editors from external providers or other content providers  108  into LMS  140  and launch the editors directly from authoring environment  210 . Authoring environment  210  often includes a number of tools for creating, structuring, and publishing course content and tests to facilitate and optimize the work of instructional designers, subject matter experts, and training administrators  105 . Authoring environment  210  may contain any number of components or sub-modules such as an instructional design editor is used by instructional designers and subject matter experts to create and structure learning content (learning nets and learning objects), a test author is used by instructional designers and subject matter experts to create web-based tests, and a repository explorer is for training administrators and instructional designers to manage content. 
     In the illustrated embodiment, course content is stored and managed in content management system  220 . Put another way, LMS  140  typically uses the content management system  220  as its content storage location for content or learning objects valid through environment  100 . But a WebDAV (Web-based Distributed Authoring and Versioning) interface (or other HTTP extension) allows integration of other WebDAV-enabled storage facilities as well without departing from the scope of this disclosure. Regardless of the particular technology, content management system  220  includes a master content repository. This master content repository, also referred to herein as the “master repository,” stores the learning objects described above, which are used to present a course to learner  104 . The master repository may also store version objects  225 , described in more detail below. Content authors or developers  106  publish content from their respective local repository (often the memory in the particular client) to the master repository. The master and local repositories may be managed via a computer program known as the repository explorer or another similar interface in authoring environment  210 . The example repository explorer may be run on the client of developer  106  and may communicate with both the local repository and the master repository. This repository explorer may includes a window or frame that displays a list of objects, along with component files, stored in the local repository and another window or that displays a list of objects stored in the master repository. Links to this content may assist the training administrator  105  in retrieving suitable course content when planning web-based courses. 
     A training management component of LMS  140  may help the training administrator  105  plan and create the course offering; manage participation, resources, and courses; and perform reporting. When planning e-learning courses, the training administrator  105  uses references inserted in published courses to retrieve the appropriate content in the content management system for the courses being planned. Content management system  220  may also include or implement content conversion, import, and export functions, allowing easy integration of Sharable Content Object Reference Model (SCORM)-compliant courses from external providers or other content providers  108 . Customers can create and save their own templates for the various learning elements (learning objects, tests, and so on) that define structural and content-related specifications. These provide authors with valuable methodological and didactical support. 
     LMS  140  and its implemented methodology typically structure content so that the content is reusable and flexible. For example, the content structure allows the creator of a course to reuse existing content to create new or additional courses. In addition, the content structure provides flexible content delivery that may be adapted to the learning styles of different learners. E-learning content may be aggregated using a number of structural elements arranged at different aggregation levels. Each higher level structural element may refer to any instances of all structural elements of a lower level. At its lowest level, a structural element refers to content and may not be further divided. According to one implementation shown in  FIG. 3 , course material  300  may be divided into four structural elements: a course  301 , a sub-course  302 , a learning unit  303 , and a knowledge item  304 . 
     Starting from the lowest level, knowledge items  304  are the basis for the other structural elements and are the building blocks of the course content structure. Each knowledge item  304  may include content that illustrates, explains, practices, or tests an aspect of a thematic area or topic. Knowledge items  304  typically are small in size (i.e., of short duration, e.g., approximately five minutes or less). Any number of attributes may be used to describe a particular knowledge item  304  such as, for example, a name, a type of media, and a type of knowledge. The name may be used by a learning system to identify and locate the content associated with a knowledge item  304 . The type of media describes the form of the content that is associated with the knowledge item  304 . For example, media types include a presentation type, a communication type, and an interactive type. A presentation media type may include a text, a table, an illustration, a graphic, an image, an animation, an audio clip, and a video clip. A communication media type may include a chat session, a group (e.g., a newsgroup, a team, a class, and a group of peers), an email, a short message service (SMS), and an instant message. An interactive media type may include a computer based training, a simulation, and a test. 
     Knowledge item  304  also may be described by the attribute of knowledge type. For example, knowledge types include knowledge of orientation, knowledge of action, knowledge of explanation, and knowledge of source/reference. Knowledge types may differ in learning goal and content. For example, knowledge of orientation offers a point of reference to the learner, and, therefore, provides general information for a better understanding of the structure of interrelated structural elements. Each of the knowledge types are described in further detail below. 
     Knowledge items  304  may be generated using a wide range of technologies, often allowing a browser (including plug-in applications) to be able to interpret and display the appropriate file formats associated with each knowledge item. For example, markup languages (such as HTML, a standard generalized markup language (SGML), a dynamic HTML (DHTML), or XML), JavaScript (a client-side scripting language), and/or Flash may be used to create knowledge items  304 . HTML may be used to describe the logical elements and presentation of a document, such as, for example, text, headings, paragraphs, lists, tables, or image references. Flash may be used as a file format for Flash movies and as a plug-in for playing Flash files in a browser. For example, Flash movies using vector and bitmap graphics, animations, transparencies, transitions, MP3 audio files, input forms, and interactions may be used. In addition, Flash allows a pixel-precise positioning of graphical elements to generate impressive and interactive applications for presentation of course material to a learner. 
     Learning units  303  may be assembled using one or more knowledge items  304  to represent, for example, a distinct, thematically-coherent unit. Consequently, learning units  303  may be considered containers for knowledge items  304  of the same topic. Learning units  303  also may be considered relatively small in size (i.e., duration) though larger than a knowledge item  304 . 
     Sub-courses  302  may be assembled using other sub-courses  302 , learning units  303 , and/or knowledge items  304 . The sub-course  302  may be used to split up an extensive course into several smaller subordinate courses. Sub-courses  302  may be used to build an arbitrarily deep nested structure by referring to other sub-courses  302 . 
     Courses may be assembled from all of the subordinate structural elements including sub-courses  302 , learning units  303 , and knowledge items  304 . To foster maximum reuse, all structural elements should be self-contained and context free. 
     Structural elements also may be tagged with metadata that is used to support adaptive delivery, reusability, and search/retrieval of content associated with the structural elements. For example, learning object metadata (LOM), per maps defined by the IEEE “Learning Object Metadata Working Group,” may be attached to individual course structure elements. The metadata may be used to indicate learner competencies associated with the structural elements. Other metadata may include a number of knowledge types (e.g., orientation, action, explanation, and resources) that may be used to categorize structural elements. 
     As shown in  FIG. 4 , structural elements may be categorized using a didactical ontology  400  of knowledge types  401  that includes orientation knowledge  402 , action knowledge  403 , explanation knowledge  404 , and resource knowledge  405 . Orientation knowledge  402  helps a learner  104  to find their way through a topic without being able to act in a topic-specific manner and may be referred to as “know what.” Action knowledge  403  helps a learner to acquire topic related skills and may be referred to as “know how.” Explanation knowledge  404  provides a learner with an explanation of why something is the way it is and may be referred to as “know why.” Resource knowledge  405  teaches a learner where to find additional information on a specific topic and may be referred to as “know where.” 
     The four knowledge types (orientation, action, explanation, and reference) may be further divided into a fine grained ontology. For example, orientation knowledge  402  may refer to sub-types  407  that include a history, a scenario, a fact, an overview, and a summary. Action knowledge  403  may refer to sub-types  409  that include a strategy, a procedure, a rule, a principle, an order, a law, a comment on law, and a checklist. Explanation knowledge  404  may refer to sub-types  406  that include an example, an intention, a reflection, an explanation of why or what, and an argumentation. Resource knowledge  405  may refer to sub-types  408  that include a reference, a document reference, and an archival reference. 
     Dependencies between structural elements may be described by relations when assembling the structural elements at one aggregation level. A relation may be used to describe the natural, subject-taxonomic relation between the structural elements. A relation may be directional or non-directional. A directional relation may be used to indicate that the relation between structural elements is true only in one direction. Directional relations should be followed. Relations may be divided into two categories: subject-taxonomic and non-subject taxonomic. 
     Subject-taxonomic relations may be further divided into hierarchical relations and associative relations. Hierarchical relations may be used to express a relation between structural elements that have a relation of subordination or superordination. For example, a hierarchical relation between the knowledge items A and B exists if B is part of A. Hierarchical relations may be divided into two categories: the part/whole relation (i.e., “has part”) and the abstraction relation (i.e., “generalizes”). For example, the part/whole relation “A has part B” describes that B is part of A. The abstraction relation “A generalizes B” implies that B is a specific type of A (e.g., an aircraft generalizes a jet or a jet is a specific type of aircraft). 
     Associative relations may be used refer to a kind of relation of relevancy between two structural elements. Associative relations may help a learner obtain a better understanding of facts associated with the structural elements. Associative relations describe a manifold relation between two structural elements and are mainly directional (i.e., the relation between structural elements is true only in one direction). Examples of associative relations include “determines,” “side-by-side,” “alternative to,” “opposite to,” “precedes,” “context of,” “process of,” “values,” “means of,” and “affinity.” 
     The “determines” relation describes a deterministic correlation between A and B (e.g., B causally depends on A). The “side-by-side” relation may be viewed from a spatial, conceptual, theoretical, or ontological perspective (e.g., A side-by-side with B is valid if both knowledge objects are part of a superordinate whole). The side-by-side relation may be subdivided into relations, such as “similar to,” “alternative to,” and “analogous to.” The “opposite to” relation implies that two structural elements are opposite in reference to at least one quality. The “precedes” relation describes a temporal relationship of succession (e.g., A occurs in time before B (and not that A is a prerequisite of B). The “context of” relation describes the factual and situational relationship on a basis of which one of the related structural elements may be derived. An “affinity” between structural elements suggests that there is a close functional correlation between the structural elements (e.g., there is an affinity between books and the act of reading because reading is the main function of books). 
     Non Subject-Taxonomic relations may include the relations “prerequisite of” and “belongs to.” The “prerequisite of” and the “belongs to” relations do not refer to the subject-taxonomic interrelations of the knowledge to be imparted. Instead, these relations refer to the progression of the course in the learning environment (e.g., as the learner traverses the course). The “prerequisite of” relation is directional whereas the “belongs to” relation is non-directional. Both relations may be used for knowledge items  304  that cannot be further subdivided. For example, if the size of the screen is too small to display the entire content on one page, the page displaying the content may be split into two pages that are connected by the relation “prerequisite of.” 
     Another type of metadata is competencies. Competencies may be assigned to structural elements, such as, for example, a sub-course  302  or a learning unit  303 . The competencies may be used to indicate and evaluate the performance of a learner as learner  104  traverses the course material. A competency may be classified as a cognitive skill, an emotional skill, a senso-motorical skill, or a social skill. 
       FIGS. 5A-B  are flowcharts illustrating example methods,  500  and  550  respectively, for developing content in accordance with certain embodiments of the present disclosure. Generally, learning content includes a plurality of learning objects. Each learning object may be considered a container of (physically or logically) associated content files such as, for example, one or more web pages with images used in the page. The following description focuses on the operation of a developer  106  using learning management system  140  and such learning objects and content files to perform this method. But environment  100  contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. 
     As shown in  FIG. 5A , a content developer  106  may use all or a portion of LMS  140  (such as authoring environment  210 ) to develop new or updated content as illustrated by example method  500 . For example, method  500  begins at step  502 , where content developer  106  creates a course structure, often according to prescribed standards and guidelines. Next, developer  106  defines dependencies between individual objects at step  504  and creates the relevant functional and didactical relationships at step  506 . Developer  106  may develop, as illustrated at step  508 , a learning objectives catalog, one or more elements of which he then assigns to the appropriate learning objects at step  510 . Then at step  512 , and as described in more example detail in  FIG. 5B , developer  106  develops the particular content for each object within the course structure. Such content may include web pages, images, Flash or other media, or any other data to be stored in content files. Of course, developer  106  may manage or work with other developers  106  (or  108 ) to develop some or all of the individual content. In this case, the particular developer  106  may specify that content is to be created by particular authors and may, also or in combination, have a coordinating function in the content creation process. This would be typically required when there are several subject matter experts involved in one course structure. Developer  106  may further be responsible for deadline and schedule monitoring. Once the content is suitably developed, he may verify that the structures are complete, that they are didactically correct, or perform any other appropriate verification or authentication at step  514 . For example, developer  106  may also check the metadata and the learning objectives. Upon completion, developer  106  publishes the (typically whole) learning net in the master repository, where it is available to training administrators  105  at step  516 . 
       FIG. 5B  provides one example technique, via method  550 , for specifically developing content for a learning course. In this method  500 , developer  106  may (or may not) load a content template at step  552 . In this case, developer  106  attempts to create instructional content, stored in content files, in close cooperation with the instructional designer using the prescribed templates. Regardless, developer  106  may identify at step  554  existing learning objects in the master repository (or content repository  220 ) that can be used or converted for the existing project. If necessary or desired, develop  106  may update one, some, or all of these existing learning objects (as well as individual content files) to make them more suitable for the particular course at step  556 . Next, at step  558 , developer  106  develops new content or content files using any appropriate editor or other program. Then, in steps  560  and  562 , developer  106  makes finished content (learning net, learning object, or media object) available to other authors  106  and administrators  105 . This typically involves checking in the content into the master repository and releasing or publishing the content. Of course, other authors can then subsequently reuse this content by copying it or creating references to it. 
     As described above, existing learning objects may be revised and/or combined to create new versions of existing objects. “Version,” in this context, is generally a learning object that is derived from, or based on, another learning object. The process of creating new versions of existing learning objects is commonly called “versioning.” In general, other versioning systems used in traditional (learning) applications may only one currently valid configuration. That is, such applications typically have a single version of each object for use in the application. By contrast, in LMS  140 , different versions of the same object can be used at the same time. Each object version “knows” on what other object versions it depends, which promotes consistency throughout the LMS  140 . Such knowledge typically arises in terms of a versioning object. Each versioning object contains multiple content files (in some cases several thousand) that can represent a single page, a chapter, or a complete course depending on the granularity used when building the course. Regardless of the particular granularity used, each versioning object may be treated as a single object; therefore, an operation performed on the object is usually performed on all component files. 
     In regard to the content files, delta versioning is used by LMS  140  to save learning objects that have actually been changed into new object versions, while at least attempting to ignore or reduce processing of unchanged content files within the learning objects. Typically, content files that are identical to (or substantially match) the precursor versions are only referenced in subsequent versioning objects. In certain embodiments, delta versioning is only be used for reusable learning objects. As described below for GUI  116   a , developer  106  can set the relevant indicator when checking content into the master repository. The anchor file is normally changed because it contains the metadata that is automatically maintained by the system for each version object. This is also the case when developer  106  only changes the metadata. LMS  140  may recognizes that a file has changed by any of its attributes or other version information including, for example, its size, a hash value, a timestamp, a version identifier, or other similar information. If the file size has not changed, it checks the date and the check sum of the file. If LMS  140  recognizes that a file is not identical to or fails to match its precursors, then it checks the file into the master repository. Delta versioning finds unchanged files in a fast and efficient way by storing the information about copied and referenced files using a data structure stored in a special file, often within the versioning object. This object version file  225  may be any suitable format operable to include the delta versioning information for the particular versioning object it&#39;s located or referenced within. For example, object version file  225  may be text, XML, HTML, SQL or other DB table, CSV, a variable and similar such data structures for storage in the versioning object. In other words, object version file  225  may contain the complete list of files which are part of this version object. Then, for each individual file, it may store its name, size, date, MD5 checksum or other hash, or any other suitable versioning information. For example, object version file  225  may include information in the following structure: 
                                            &lt;?xml version=“1.0” encoding=“UTF-8” ?&gt;           &lt;LSODELTAVERINFO REUSEOBJ=“/Test/Styleguide_for_e-                 Learning_Content/v1/” VERSION=“1”&gt;                         &lt;FILE PATH=“graphics/manufactured_courseware2.jpg”                 SIZE=“33220” DATE=“106BBC5FFB8”       HASH=“DGwBTmtNtXuDxQPab0ETBg==“ /&gt;                         &lt;FILE PATH=“course_overview2.htm” SIZE=“4739”                 DATE=“106BBC5FFB8” HASH=“Zgqc4AzHnAOtXw7t0G+xKQ==“ /&gt;                         &lt;FILE PATH=“Storyboard Template for IEs.doc”                 SIZE=“248832” DATE=“106BBC5FFB8”       HASH=“LpZJ7z/sUl8WlwUQfwju5Q==“ /&gt;                         &lt;FILE PATH=“goals_objectives.htm” SIZE=“1560”                 DATE=“106BBC5FFB8” HASH=“bjyHTK1F8mMhs6qcZ6cq7w==“ /&gt;                         &lt;FILE PATH =“business_example.htm” SIZE=“2011”                 DATE=“106BBC5FFB8” HASH=“ta3AwYsVrJz9Fg+ByR2nYg==“ /&gt;                         &lt;FILE PATH=“main.crs” SIZE=“6824” DATE=“106BBC5FFB8”                 HASH=“QegFVt7jhN9qVCUVHXR1eg==“ /&gt; ‘                         &lt;FILE PATH=“Storyboard Template for LN.doc”                 SIZE=“136704” DATE=“106BBC5FFB8”       HASH=“7IwHmn0UssLRPOSoVopTfg==“ /&gt;                         &lt;FILE PATH=“002006825000000584722001E.css” SIZE=“5197”                 DATE=“106BBC5FFB8” HASH=“QndHXfzj8gL4nynST1TFwQ==“ /&gt;                         &lt;FILE PATH=“welcome.htm” SIZE=“4233”                 DATE=“106BBC5FFB8” HASH=“Y5RjNe+oT5vBIoi8xgg9iw==“ /&gt;                         ...                         &lt;/LSODELTAVERINFO&gt;                        
If a copy of the particular content file is already present in a prior version of the object, then the relative path to this file is also stored. For initial versions of objects or new versions of non-delta versioned objects, then there may be no relative link to a prior version. Returning to the example structure above, the developer  106  may have updated one content file within the particular learning object, namely main.crs. This would result in a new object version file as follows:
 
                                            &lt;?xml version=“1.0” encoding=“UTF-8” ?&gt;           &lt;LSODELTAVERINFO REUSEOBJ=“/Test/Styleguide_for_e-                 Learning_Content/v2.775724959658401894/” VERSION=“1”&gt;                         &lt;FILE PATH=“graphics/manufactured_courseware2.jpg”                 SIZE=“33220” DATE=“106BBC5FFB8”       HASH=“DGwBTtmtNtXuDxQPab0ETBg==“       REFPATH=“../v1/graphics/manufactured_courseware2.jpg” /&gt;                         &lt;FILE PATH=“course_overview2.htm” SIZE=“4739”                 DATE=“106BBC5FFB8” HASH=“Zgqc4AzHnAOtXw7t0G+xKQ==“       REFPATH=“../v1/course_overview2.htm” /&gt;                         &lt;FILE PATH=“Storyboard Template for IEs.doc”                 SIZE=“248832” DATE=“106BBC5FFB8”       HASH=“LpZJ7z/sUl8WlwUQfwju5Q==“ REFPATH=“../v1/Storyboard       Template for IEs.doc” /&gt;                         &lt;FILE PATH=“goals_objectives.htm” SIZE=“1560”                 DATE=“106BBC5FFB8” HASH=“bjyHTK1F8mMhs6qcZ6cq7w==“       REFPATH=“../v1/goals_objectives.htm” /&gt;                         &lt;FILE PATH=“main.crs” SIZE=“6844” DATE=“106BF7C58C8”                 HASH=“QegFVt7jhN9qVCUVZ2R1eg==“ /&gt;                         ...                         &lt;/LSODELTAVERINFO&gt;                        
Of course, the foregoing examples are for illustration purposes only and may not represent the data, the structure, the metadata, or the format used in learning management systems  140 .
 
     To develop or update such content files and the respective learning objects, content developers  106  work in their local repositories. The local repository allows the developer  106  to copy objects from the master repository (as read-only objects) and to create and edit new learning object versions. Objects created in local repositories can be copied and stored back in the master repository. LMS  140  also allows users to “use” objects (via references) without storing the objects in their local repositories. So long as developer  106  does not decide to move object versions to and/or from the master repository, the user can work in a local repository without being connected to the master repository. This work model is often termed the “offline scenario.” Similarly, working in the local repository, while being connected to the master repository, is termed the “online scenario.” To this end, storing objects from the local repository into the master repository is known as “checking-in.” Check-in enables data transfer from the local repository to the master repository. Data is stored in the master repository and can be displayed by other authors when it has been released. When developer  106  checks in content, a check-in wizard (illustrated in  FIGS. 6A-D ) may guide him through the process. With the check-in wizard, the user can also automatically add all dependent objects to the check-in list. Dependent objects are other objects generally required for displaying the object being checked in. 
     The check-in wizard offers a number of options, which developer  106  select by marking the relevant checkbox. Before check-in, developer  106  can run a consistency check on the cross-references between the objects and their dependencies. As described by  116   a  in  FIG. 6A , developer  106  can also select the indicator Use Delta Versioning When Saving to Master Repository. With this option, only files that developer  106  changed in new versions of learning objects are checked in. Files in versioning objects that were not changed are transferred or referenced from the precursor versions. Developer  106  can select the indicator “Automatically consider files older than checked-in version as unchanged.” With this option, such files are not included in the check-in. GUI  116   a  also presents developer  106  with the ability to delete copies of the object in the local repository after they have been checked in. As illustrated, example GUI  116   a  also has other options including, after check-in, the ability to automatically release the checked in objects and the ability to have learning nets automatically published when they have been released.  FIGS. 6B-D  illustrate further steps of the check-in wizard implementing certain delta versioning techniques, namely the current status of process (GUI  116   b ), a confirmation status page indicating the status of the particular version objects (GUI  116   c ), and a drill down window presenting detailed file information for the components of the selected version object (GUI  116   d ).  FIGS. 7A-B  illustrate example views into the master repository. For example, GUI  116   e  presents the versioning object as it resides in the master repository and implementing the first example version structure above. In this illustration, GUI  116   e  presents details of learning object “Styleguide for content.” This version of the learning object includes object version file  225 , named  — 1sodeltaverinfoXQ7_.gz, and the plurality of content files included in the learning object. These example content files include main, course overview, intro, extro, and others. After developer  106  creates a new version of the learning object by changing the example main.crs file, the new versioning object is loaded into the master repository, resulting in the updated view via GUI  116   f . This example versioning object does not include most of the individual files and instead references them from prior versions. Typically, as described above, the object version file  225  would be used to store such information. 
     In rare cases, LMS  140  may determine a version conflict during check-in. Such a conflict occurs when the objects to check-in indirectly reference different versions of an object. When this happens, developer  106  may select the version to use in the context of the objects checking in. For example, the check-in wizard may display a step that refers to a structural error in the object checking in. In this case, developer  106  can ignore such errors and proceed with the check-in. Alternatively, developer  106  can cancel the check-in and correct the errors. For example, if not all dependent objects are included in the list, then developer  106  may leave the check-in wizard and edit the dependencies in the local repository. LMS  140  often detects version conflicts by determining that dependant objects of an object to be checked in reference different versions of the same common object, and resolves the conflicts appropriately, as described below. To this end, two “conflict rules” are defined by LMS  140 , which are followed in each repository interaction. According to the “first rule,” each object version within the master repository must be conflict free, meaning that each object version must not reference, directly or indirectly, any other object in more than one version. According to the “second rule,” each local repository must be conflict free, meaning that each local repository must not contain any object in more than one version. In this context “contains” means that a version of an object is either physically stored in the local repository or is referenced from another object that is stored in the local repository. Separation into two rules generally helps the conflict check process to be relatively easy and efficient. For example, compliance with the first rule need be checked only when new objects are checked-in to the master repository. Compliance with the second rule can be checked locally (even in an offline scenario) without regard to the master repository. 
       FIG. 8  is a flowchart illustrating an example method  800  for implementing delta versioning in accordance with certain embodiments of the present disclosure. As with  FIGS. 5A-B , the following description focuses on the operation of learning management system  140  in performing these methods. But environment  100  contemplates using any appropriate combination and arrangement of logical elements implementing some or all of the described functionality. Method  800  begins at step  802 , where learning management system  140  receives a request to store content from content developer  106 . At step  804 , learning management system  140  identifies the first learning object from the content to store. Learning management system  140  loads and parses object version files  225  of previous versions belonging to the particular learning object at step  806 . Learning management system  104  may also instantiate or otherwise generate a new versioning object associated with the particular learning object. Learning management system  140  parses the new version object into the associated content files (in the individual learning object) at step  808 . Next, learning management system  140  creates a new entry in object version file  225  for each found file at step  808 . Then, at step  811 , learning management system  140  identifies the first content file in the particular learning object and determines versioning information of the particular content file at step  812 . As described above, this version information may include a hash value, a size, a name, a date or timestamp, a version number, or any other information operable to at least partially identify the particular version. 
     At this point, learning management system  140  then identifies the versioning information of the same file as present in prior versioning objects of the particular learning object at step  814 . Next, learning management system  140  compares the identified versioning information of the prior versions with the determined version information of the current content file at step  816 . If this versioning information matches with version information from a prior object version as illustrated at decisional step  818 , then learning management system  140  stores a relative path to the previously stored content file in the entry of the new object version file at step  820  and processing proceeds to step  826 . Otherwise, learning management system  140  determined that the particular content file is a new version of the file and is apparently different (or distinguishable) from versions of this file found in prior object versions. In this case, it then stores this new version of the content file (as part of the object version) in content repository  220  (or the master repository) at step  822 . As part of this storage process, learning management system  140  may store new path and versioning information of file in entry of object version file. Once this loading processing is complete for this particular content file, then learning management system  140  determines if there are more content files to be stored from version object at decisional step  824 . If there are, it identifies the next content file in the particular learning object at step  825  and processing returns to step  812 . Otherwise, learning management system  140  determines if there are more learning objects to be processed. If there are, then learning management system  140  identifies the next learning object and processing returns to step  806 . Used in this or other similar ways, learning management system  140  (or authoring environment  210 ) do not have to send every of the plurality of files associated with the particular versioning object of a learning object. Instead, only those files that have been updated have to be sent, thereby saving time, storage space, and money. Once there are no more learning objects to be processed, then learning management system  140  may send confirmation of the stored content at step  830 . As described above, this confirmation may be updating the web site, sending an e-mail, sending a text message, or any other appropriate confirmation technique. 
     The preceding flowcharts and accompanying descriptions illustrate exemplary methods  500 ,  550 , and  800 . But environment  100  contemplates using any suitable technique for performing these and other tasks. Accordingly, many of the steps in these flowcharts may take place simultaneously and/or in different orders than as shown. Moreover, environment  100  may use methods with additional steps, fewer steps, and/or different steps, so long as the methods remain appropriate. For example, it will be understood that content developer  106  may perform some or all of the processing described by method  500 , while developing content in a process similar to, but different from, method  550 . 
     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.