Tuesday, September 27, 2011

An e-learning system for standard compatible and uniform course development.

An e-learning system for standard compatible and uniform course development. This article introduces the architecture and implementation of anauthoring system capable of modular and standard compatible coursedevelopment. This system enables the aggregation of learning objectsinto higher course structures and reuse reuse - Using code developed for one application program in another application. Traditionally achieved using program libraries. Object-oriented programming offers reusability of code via its techniques of inheritance and genericity. in different learning scenarios.The concept of modular course development is based on the constructionkit metaphor for e-learning systems that represents a general solutionfor specific content creation and publishing. The learning objects areimplemented as IMS (1) See IP Multimedia Subsystem.(2) (Information Management System) An early IBM hierarchical DBMS for IBM mainframes. IMS was widely implemented throughout the 1970s under MVS and continues to be used under z/OS. Content Packages containing a special asset coded inXML XMLin full Extensible Markup Language.Markup language developed to be a simplified and more structural version of SGML. It incorporates features of HTML (e.g., hypertext linking), but is designed to overcome some of HTML's limitations. . The XML document consists of the semantical content of learningobjects without defining a specific format and layout. The authoringsystem facilitates the composition and aggregation process of learningobjects for designing standard compatible and uniform courses used byinstructors and students through Learning Management Systems (LMS (Learning Management System) An information system that administers instructor-led and e-learning courses and keeps track of student progress. Used internally by large enterprises for their employees, an LMS can be used to monitor the effectiveness of the ). INTRODUCTION Today, there is an ever increasing demand for multimedia onlinecourses, scientific curriculums, and learning units; a wide range ofe-learning content to help students and professors in higher education higher educationStudy beyond the level of secondary education. Institutions of higher education include not only colleges and universities but also professional schools in such fields as law, theology, medicine, business, music, and art. has already been developed. Professors use multimedia courses in theirlectures to convey complex topics while students use them online toincrease their knowledge or explore materials in detail. In most cases,however, the content already developed can neither be reused by otherauthors nor used in an interdisciplinary manner. This is becauseauthoring tools, such as Macromedia Authorware Macromedia Authorware (now part of Adobe Systems) is an interpreted, flowchart based, graphical programming language. Authorware is used for creating interactive programs that can integrate a range of multimedia content, particularly e-learning applications. , Macromedia Dreamweaver,Click2Learn Toolbook, or LRN LRN Linux.ru.net (website)LRN Laboratory Response NetworkLRN Location Routing NumberLRN Local Routing NumberLRN Learning Resource iNterchange (Microsoft)LRN Lead Round Nose Toolkit do not support the development ofmodular learning objects as Hodgins (2002) or Wiley (2000) haveintroduced. With these systems, it is not possible to take learningobjects and to put them together like LEGOs. The reason is that mostauthoring systems do not provide modular course structures that allowthe user to extract parts of the course and combine them with othercourses. Although many tools, such as LRN Toolkit, provide exportfilters using IMS Content Packaging (IMS, 2002), their results cannot bemerged to build consistent and uniform courses that can be reused in aninterdisciplinary manner. This is caused by the lack of separationbetween the definition of the content and its representation. Imagine a basic mathematics course on complex numbers: For example,an online course in the field of machine dynamics requires knowledge ofcomplex numbers for the explanation of Harmonic harmonic.1 Physical term describing the vibration in segments of a sound-producing body (see sound). A string vibrates simultaneously in its whole length and in segments of halves, thirds, fourths, etc. oscillations oscillationsSee Cortical oscillations. . Inadditon, the basic courses, mathematics for engineers and technicalcomputer science, require complex numbers to enhance the topicexponential function exponential functionIn mathematics, a function in which a constant base is raised to a variable power. Exponential functions are used to model changes in population size, in the spread of diseases, and in the growth of investments. , sine and cosine cosine:see trigonometry. See sine. COSINE - Cooperation for Open Systems Interconnection Networking in Europe. A EUREKA project. in the complex plane. No authoringtool supports a simple integration of content written by differentauthors or generates a consistent visualization Using the computer to convert data into picture form. The most basic visualization is that of turning transaction data and summary information into charts and graphs. Visualization is used in computer-aided design (CAD) to render screen images into 3D models that can be viewed from all of them. In order to address this problem, the project Math-kit (1) (Unger,Oevel, & Mertsching, 2002; Mathkit, 2004) developed the Math-kitauthorware, which consists of the authoring system Lyssa and theplatform CKS CKS ChecksCKS Center for Korean Studies (UC Berkeley)CKS Center for Knowledge SocietiesCKS Carajas, Para, Brazil - International / Brasilia Brazil (Airport Code)CKS Crankshaft Sensor (Construction Kit Server), for the creation of technicaland modular learning units for interdisciplinary use in highereducation. This authoring system enables the development of semanticallearning units without definining style or layout. Due to the strictseparation of style and layout, authors can use learning units developedby other authors and integrate them into their own courses. This enablesthe transformation of each course into a specific format with anindividual layout definition. Moreover, learning content alreadyavailable and based on authoring tools such as Microsoft Word A full-featured word processing program for Windows and the Macintosh from Microsoft. Included in the Microsoft application suite, it is a sophisticated program with rudimentary desktop publishing capabilities that has become the most widely used word processing application on the market. or Latexcan be integrated easily. For this purpose, special import filters areincluded to provide a mapping of the content of the documents to thecourse structure of the authoring system. During the development of the system, the metaphor, a constructionkit (Bungenstock, Baudry, & Mertsching, 2002), was used; thisprovided both authors and software developers with a commonunderstanding of its architecture and usage. In this metaphor, reusable re��use?tr.v. re��used, re��us��ing, re��us��esTo use again, especially after salvaging or special treatment or processing.re��us learning objects (RLO RLO Reusable Learning ObjectRLO Resident Liaison Officer (UK)RLO Records Liaison OfficerRLO Regional Liaison OfficeRLO Reserve Liaison OfficerRLO Richland Operations (US DOE)) (Wiley, 2000; Hodgins, 2002; Heng, 2003; Downes,2000) resemble bricks in a conventional construction kit, which can bereused in different contexts and education scenarios. The metaphorcovers the process of development, composition, and publication ofmodular e-learning content and also solves problems arising from thecombination of bricks, like the consistent composition of coursestructure and presentation. This system has been used effectively within the joint projectmathkit at the German universities of Hamburg Hamburg, city, GermanyHamburg(häm`brkh), officially Freie und Hansestadt Hamburg (Free and Hanseatic City of Hamburg), city (1994 pop. (2), Bayreuth, Hagen, andPaderborn. At these universities, several mathematics learning unitswere developed and integrated into courses including disciplines likemathematics for mechanical engineering, mathematics for computerscience, technical computer science, and the correspondence course,linear algebra linear algebraBranch of algebra concerned with methods of solving systems of linear equations; more generally, the mathematics of linear transformations and vector spaces. . First, this article describes the bases of the construction kitapproach and how the authoring system Lyssa was implemented. Second, itprovides an example of modular and standard compatible coursedevelopment. THE CONSTRUCTION-KIT METAPHOR During the software engineering process, metaphors are used by thedeveloper team to get a better and more uniform understanding of aparticular problem that a software system should be capable of solving.Metaphors of this kind also support the communication between users anddevelopers. During the design phase of the Math-kit system, the metaphor of aconstruction kit was used. A conventional construction kit consists ofbricks, models, and sometimes construction plans. Bricks can beassembled to form different models. The organization of these models maybe described by a construction plan, which helps a user to understandthe complex structure. The construction kit itself stores the bricks,models, and plans. With reference to the e-learning system Math-kit, theterms of the construction kit metaphor for e-learning systems can bedescribed as follows: The bricks resemble learning objects (LOBs), whichcan be integrated into courses. These are the smallest units forexchange and are independent from each other. The models are courseobjects (COBs) consisting of learning objects and of other courseobjects. The construction kit resembles the Math-kit systemadministrating the dynamic behavior, which includes the search orarchivation of LOBs and COBs. The technical realization of bricks and models was inspired by thesharable content object (SCO (The SCO Group, Lindon, UT, www.sco.com) A leading vendor of Unix operating systems for the x86 platform. SCO had also offered Linux, but abandoned the line in the spring of 2003. The SCO Group is the combination of two companies: Utah-based Caldera, Inc. ) of the SCORM SCORM Shareable Content Object Reference Model (web-based e-learning standard)SCORM Shared Courseware Object Reference ModelSCORM Shareable Courseware Object Reference Model standard (ADL, 2004). Inbrief, an SCO represents a collection of various resource files (theassets) and is the smallest learning unit of a Learning ManagementSystem (LMS). An SCO is defined as independent unit to be reused indifferent learning contexts and communicates data by an LMS viaspecified application program interfaces (APIs). It uses the IMS contentpackage mechanism for the bundling of course structures, resource files,and metadata into a single file (the manifest). SCORM offers two typesof content packages; resource packages and content aggregation packages.The resource packages only contain asset files such as images or videos.In contrast, content aggregation packages contain other resource oraggregation packages, so that higher-level structures like lessons,learning units, or complete courses can be built. In the construction kit metaphor, resource packages are used todefine the LOB, whereas COBs are realized as content aggregationpackages. Although the SCO approach meets the demands for contentinterchange and execution with applications it does not support theseparation of content and view, which is one of the essential goals ofMath-kit. Therefore, an LOB has the same structure as a resource packagewith one exception and special asset: a document file based on theExtensible Markup Language See XML. (language, text) Extensible Markup Language - (XML) An initiative from the W3C defining an "extremely simple" dialect of SGML suitable for use on the World-Wide Web.http://w3.org/XML/. (XML) (W3C (World Wide Web Consortium, www.w3.org) An international industry consortium founded in 1994 by Tim Berners-Lee to develop standards for the Web. It is hosted in the U.S. by the Computer Science and Artificial Intelligence Laboratory (CSAIL) at MIT (www.csail.mit.edu/index.php). , 2004). The need for such acontent separation was also considered by the SCORM Dynamic AppearanceModel (Canadian Department of National Defence, 2002). However, since itmainly focuses on the common appearance of the navigation, it does notmeet the requirements of the Math-kit project. ARCHITECTURE Roles Roles are necessary for modeling different views of the Math-kite-learning system. It is important to understand that a person canappear in several roles. The roles help to model the static and dynamicbehavior of the system with different use-cases and sequential diagrams(Bergner, Rausch, & Sihling 1998) in order to gain a strict andcontrollable development process. The roles defined within Math-kit arethe following: instructor, student, composer, LOB developer, publisher,and administrator. * Instructor: The instructor uses single blocks or complete coursesto extend his/her own lectures or to create new ones. Importantoperations for this role are searching, archiving, and presentation ofcourses and LOBs. * Student: This role requires similar operations albeit for anotherpurpose. Individuals in this role want to learn something and are ableto explore the entire database using LOBs and courses of interest. Thesetwo roles are not directly dependent on the construction kit metaphorbecause they work with Math-kit through an LMS or access the courseswith a simple Web browser The program that serves as your front end to the Web on the Internet. In order to view a site, you type its address (URL) into the browser's Location field; for example, www.computerlanguage.com, and the home page of that site is downloaded to you. . Nevertheless, the construction kit is thebasis of the created content. * Composer: The composer combines existing LOBs and courses tobuild new ones. Useful operations of this role include the search forLOBs, their combination, preview, and editing. This role creates andedits the content package. In relation to the construction kit metaphor,the composer defines the construction plan. * LOB developer: The LOB developer designs and implements new LOBs.This role consists of the collection and assemblage assemblage:see collage. assemblageThree-dimensional construction made from household materials such as rope and newspapers or from any found materials. of images, text, andanimations into LOBs. In the view of the metaphor, the LOB developermerely creates bricks containing semantically defined learning contentbased on XML. * Publisher: The publisher translates semantically defined LOBsinto a readable read��a��ble?adj.1. Easily read; legible: a readable typeface.2. Pleasurable or interesting to read: a readable story. format. The main operations of the publisher are thedefinition or the selection of particular layouts and the compilation ofthe source document into a destination format. * Administrator: The administrator installs basic packages andsoftware for the construction-kit. The main task is to help the otherroles and to act as troubleshooter. Further important operations aremaintenance, consultation, and user administration. A small example should clarify the relationships between the roles.Imagine a professor intending to extend and existing lecture inelectrical engineering electrical engineering:see engineering. electrical engineeringBranch of engineering concerned with the practical applications of electricity in all its forms, including those of electronics. with a multimedia course and exercises. The firstrole will be that of the composer. Math-kit offers a wide range ofcontent and, at best case, most of the required themes are available. Ifsome content is missing or needs to be adapted, the professor takes onthe role of the LOB developer. For instance, the LOB developer is ableto enhance the technical content of the course by integratingmathematical content acquired from a colleague and not yet stored inMath-kit. Figure 1 illustrates the roles of creating a course forelectrical engineering. After the course has been completed, another person, e.g., ascientific assistant, takes over the role of the publisher. Theuniversity emblem or any other stylistic sty��lis��tic?adj.Of or relating to style, especially literary style.sty��listi��cal��ly adv. features such as font fontor typeface or type familyAssortment or set of type (alphanumeric characters used for printing), all of one coherent style. Before the advent of computers, fonts were expressed in cast metal that was used as a template for printing. ,background color, or page size can be adjusted. The product, a viewabledocument in a prefered format, can then be used by the professor--in therole of instructor--in the lecture to illustrate complex themes withanimations. If students do not understand all points of the lecture,they can read the complete course at home online. Moreover, intructorscan build more substantial courses with exercises, exploration tools andanimations. If students require more detailed information, for exampleabout complex numbers, they will be able to access the entire contentdatabase. Additionally, the student is able to work through specialexploration units also provided by the professor. The role of theadministrator does not appear in this example since this role is onlyintended as support for the other roles. Construction Kit Understanding the realization of the construction kit requires alook at its architecture (Baudry, Bungenstock, & Mertsching, 2002a).Students usually use online courses through an LMS such as ILIAS ILIAS Integriertes Lern-, Informations- und Arbeitskooperations System (German open source learning management system)(2004),LON-CAPA (2003), or Blackboard (1) See Blackboard Learning System.(2) The traditional classroom presentation board that is written on with chalk and erased with a felt pad. Although originally black, "white" boards and colored chalks are also used. (2003). An LMS provides differentcategories, e.g., communication with other students, distribution ofsolutions for exercises that accompany lectures, work through courses,or use of multiple choice tests in order to check individual learningprogress. The courses can be created with the help of authoring tools,e.g., Macromedia's Authorware (Macromedia, 2005) application. Toolslike these, however, can only be used for universal content creation.They provide solutions for quizzes or enable the author to adjustpredefined design properties. Within the Math-kit project, a specialmechanism for the definition of individual learning content is required.On the one hand, LOBs should be combined and transformed into individualcourses. Therefore, an authoring tool must provide for the possibilityof defining LOBs without any style definition. On the other hand,different output formats should be provided as well. Consequently, itwould seem that, for example, an abstract mechanism for the definitionof equations is required. [FIGURE 1 OMITTED] Starting from these facts, an arbitrary LMS or Web browser is usedto provide the content of Math-kit. This enables students andinstructors to use their favorite Web browser to work through thecourses or to select a special course block for presentations withinlectures. In order to meet our requirements, however, the process ofcontent creation must be supported by special tools. According to according toprep.1. As stated or indicated by; on the authority of: according to historians.2. In keeping with: according to instructions.3. therole concept, the LOB developer, the composer, and the publisher areexperts in content creation and each of them has a specific tool. Inrelation to our construction kit approach, these tools work with aserver storing COBs and LOBs. Therefore, the CKS is an important extension of an existing LMS forindividual content creation. Figure 2 illustrates an e-learning systemconsisting of an LMS and Math-kit components, which truly forms acontruction kit. The tools are divided into two groups: The first one isdistribution and the second is development. The development tools areused for the production of COBs that will be distributed to instructorsand students. The tool for the LOB developer creates new LOBs that canbe stored into the CKS. It enables the developer to create or modify theXML document easily by integrating new assets, for instance, images,text, or applets. [FIGURE 2 OMITTED] The developer works with a copy of the original LOB file stored inthe construction kit server. When the LOB is saved, the client workswith its own copy of the LOB merged with the original file. A separateauthoring tool is available for the composer role. This tool helps inthe process of combining LOBs to create COBs. Therefore, a manifest file A manifest file is a file contained within a JAR archive. It is used to define extension and package related data. It is a meta data file that contains name-value pairs organized in different sections. containing the structure of the course has to be created. In relation tothe construction-kit metaphor, the manifest file resembles theconstruction plan. Another tool is available for the publisher for transforming COBsinto courses that can be stored into different LMSs. With the help ofthis authoring tool, an individual design and layout can be defined. TheCKS uses transformers generated by the tool of the publisher totransform a COB into a special output format like a PDF (Portable Document Format) The de facto standard for document publishing from Adobe. On the Web, there are countless brochures, data sheets, white papers and technical manuals in the PDF format. . The publishermay opt to choose a pre-defined layout, modify an existing layout, ordefine a new layout. The consumers of the learning content do not pay attention to theCKS. They only have to access an LMS to work through courses or to usesingle LOBs for lectures. If no LMS is available, Math-kit offers thepossibility of accessing the content with simple browsers. REALIZATION This section describes the basic concepts of the authoring systemderived from the role definition of the construction-kit metaphor. Theseresults lead to an application called Lyssa (3) (Bungenstock, Baudry,& Mertsching 2003) that is responsible for the creation of bricks,their combination to models, and their publication. LOB Development Editing XML Content The first step in creating new e-learning content is to aggregatedifferent files of different types into single bricks. For best resultsand media independent production, it is recommended that the describedXML templates to create LOBs be used (Baudry, Bungenstock, &Mertsching, 2002b; NetQuest 2003; Wollowski, 2002; Kohlhase, 2002). Forthe LOBs used in the Math-kit project, an XML-scheme facilitates thedevelopment of mathematical content. The resulting markup language markup languageStandard text-encoding system consisting of a set of symbols inserted in a text document to control its structure, formatting, or the relationship among its parts. The most widely used markup languages are SGML, HTML, and XML. iscalled MathkitML and is divided into three groups of elements:structure, mathematics, and multimedia. The structure element groupcomprises tags for the definition of, for example, itemization i��tem��ize?v. i��tem��ized, i��tem��iz��ing, i��tem��iz��esv.tr.1. To place or include on a list of items: itemized her expenses on the proper form.2. ,enumeration 1. (mathematics) enumeration - A bijection with the natural numbers; a counted set.Compare well-ordered.2. (programming) enumeration - enumerated type. , or table environments. For the mathematical group Noun 1. mathematical group - a set that is closed, associative, has an identity element and every element has an inversegroupsubgroup - (mathematics) a subset (that is not empty) of a mathematical group , elementsfor definitions, theorems This is a list of theorems, by Wikipedia page. See also list of fundamental theorems list of lemmas list of conjectures list of inequalities list of mathematical proofs list of misnamed theorems Existence theorem , proofs, lemmas This following is a list of lemmas (or, "lemmata", i.e. minor theorems, or sometimes intermediate technical results factored out of proofs). See also list of axioms, list of theorems and list of conjectures. , and equations are available.The last group contains a collection of elements for the definition ofmultimedia objects such as images, audio streams, video streams, or quizenvironments. However, MathkitML does not support tags for thedefinition of books, chapters, or sections in the way DocBook (Walsh& Muellner, 2002) does. This decision was made in accordance withthe design goals of Math-kit, which are granularity The degree of modularity of a system. More granularity implies more flexibility in customizing a system, because there are more, smaller increments (granules) from which to choose. and reuseability.Standards such as IMS content packaging have defined the structure ofcourses separately so as to make sections and chapters exchangeable.Consequently, sections and subsections should not be defined in the XMLdocument but rather in the COB. Integration of Course Material The integration of existing e-learning content and documents intonew online courses is a fundamental problem within the development ofmodular courses. Although there is a wide range of authoring tools suchas Macromedia Autorware, Macromedia Dreamweaver, or Microsoft Word, eachhas its individual concept, technical realization, and data format. Theextraction of text and structures is exceedingly ex��ceed��ing��ly?adv.To an advanced or unusual degree; extremely.exceedinglyAdverbvery; extremelyAdv. 1. difficult and isimpossible in Macromedia Authorware. The main problem is caused by thecombination of structure, layout, and content. For the partial reuse ofcontent, the structure of the document must be separated from itscontent. However, most authoring systems do not support such adispartment. For instance, Microsoft Word has its own hidden dataformat, which cannot be reused by other programs and does not supportthe extraction of the document structure. In order to facilitate the course development process, Lyssasupports the integration of existing materials like Microsoft Word,DocBook, or Latex. Therefore, documents must be converted into modularCOBs. Figure 3 illustrates several components and files involved in thebrick creation process. On the left side, some programs for contentcreation and their related output files are shown. These files areconverted by associated loaders of the document processing Processing text documents, which includes indexing methods for text retrieval based on content. See document imaging. framework.The loaders use the document framework for the creation of modular COBsthat can be used in a myriad of situations. On the right side, COBs canbe aggregated and published in the desired standard format by Lyssa. Course Development Where a set of LOBs is available, they can be combined oraggregated into higher structures--the COBs. The construction kitmetaphor calls it a model, but for a particular use names like course,chapter, or section are more appropriate. For consistency, the followingexplanation uses the term model. Figure 4 illustrates the process ofmodel creation. An abstract view on the aggregation process is shown ina). Lyssa reads several bricks and aggregates them into one model. Animportant aspect of the definition is the recursive See recursion. recursive - recursion use of models.Bricks can be combined in the same way as models. This allows anindividual structure of the contents and offers several possibilities ofreuse. It then becomes possible to create LOBs, structures, chaptersetc. with less effort. The process with internal structure details isshown in b). In this illustration, a tree is used inside Lyssa for thearrangement of different bricks and models, although every other kind ofrelationship, e.g., list and net, is conceivable con��ceive?v. con��ceived, con��ceiv��ing, con��ceivesv.tr.1. To become pregnant with (offspring).2. . These different datastructures influence the appearance and the sequencing of the samecontent. For this reason, Lyssa uses one independent list of all bricksincluded and allows the definition of several navigation paths. [FIGURE 3 OMITTED] [FIGURE 4 OMITTED] Course Publishing The models or COBs, however, cannot be accessed by students orinstructors since the content is written in XML and neither style norlayout is defined. For this purpose, Lyssa includes a documentprocessing framework called Nyx (Baudry, Bungenstock, & Mertsching,2003). This transforms the LOB and COB packages into consistent onlinecourses that can be integrated into learning management systems, likeBlackboard or ILIAS. These courses can also be viewed by standardcompatible course browsers, such as Microsoft LRN Viewer, supportingboth the IMS content package and SCORM standard. The creation and distribution of uniform e-learning content is animportant aspect of the Math-kit project. To meet this demand, Lyssaprovides an easy mechanism for the definition or adaptation ofpresentation formats, layouts, and styles. The style and layout rulesare stored separately in a package called Transformation Package, whichcontains all necessary files and settings that are used for thepresentation. The concept of transformation packages enables professorsto use many different output formats by only selecting a specificpackage. In addition, the packages can be configured con��fig��ure?tr.v. con��fig��ured, con��fig��ur��ing, con��fig��uresTo design, arrange, set up, or shape with a view to specific applications or uses: by a set of plugins forspecial tasks such as the conversion of different representations ofequations to achieve a consistent and uniform presentation. Figure 5illustrates the framework, configured with two transformation packages:one for HTML HTMLin full HyperText Markup LanguageMarkup language derived from SGML that is used to prepare hypertext documents. Relatively easy for nonprogrammers to master, HTML is the language used for documents on the World Wide Web. and the other for the PDF generation. A plugin is alsoavailable to convert formulas into images or MathML. [FIGURE 5 OMITTED] To develop such a framework, it is necessary to analyse thepossible output formats. The Math-kit project uses HTML and PDF, whichdiffer in format, usage, and technique. For example, an HTML documentconsists of many linked assets; a frameset The HTML tag that divides a Web page into sections (frames). The following HTML divides the screen page into two horizontal frames with the top frame having 25% of the screen and the bottom frame having 75%. See frames.<frameset rows=25%, 75%"> </frameset> re> consists of many HTMLdocuments. A PDF document, in contrast, is a single file in which imagesare integrated as binaries. Additionally, PDF documents are useful forpresentations in lectures and printing and for allowing students tobrowse HTML documents online. Generating these documents is entirelydifferent. For instance, to build a PDF document in the field ofmathematics, a pdflatex compiler compilerComputer software that translates (compiles) source code written in a high-level language (e.g., C++) into a set of machine-language instructions that can be understood by a digital computer's CPU. is required. In the case of HTML courses, a frameset is needed to display aseparate navigation site. To make Lyssa independent of output formats,data necessary for the transformation process are stored separately intransformation packages. The transformation packages consist of aconfiguration file, transformers, and resources. The configuration filestores important settings needed for the transformation process. Forinstance, it has a flag, which decides whether or not the output isSCORM compatible. It also specifies tasks supporting the initiation andfinalization Writing the table of contents (TOC) on a recordable CD or DVD disc. The finalization process ensures that the disc can be played back on most CD and DVD players. See disc-at-once. process of the transformation. With these, format dependentactions, such as the execution of pdflatex, can be started. Twotransformers based on XSL (eXtensible Stylesheet Language) A standard from the W3C for describing a style sheet for XML documents. It is the XML counterpart to the Cascading Style Sheets (CSS) in HTML and is compatible with CSS2. stylesheets (W3C, 2004b) or Java classes arealso contained to transform the XML content of the LOBs and the coursestructure of the COBs to build the course. The transformation packagecontains resources like images needed by specific layouts and styles.With such a strict separation, a course layout change can be achieved bychanging a transformation package. Mathematical formulas in Math-kit As mentioned above, the focus of the Math-kit project is on thecreation of mathematical content. Many formulas and equations arerequired for these courses. Their definition and presentation, however,is not consistent, because there are several ways to define equations;these include MathML (W3C, 2002) and Latex. Due to the demands of theproject Math-kit, MathML is a good solution for formula presentationbecause it is based on XML and various applications, such as OpenOffice,support MathML. Unfortunately, only some browsers, e.g., the Mozillabrowser Mozilla browser may refer to one of the following web browsers produced by the Mozilla Foundation: Mozilla Application Suite Mozilla Firefox (previously known as mozilla/browser, Phoenix and Mozilla Firebird) Camino , are able to support MathML in a satisfactory way. This is whymost online courses use images for the presentation of equations. Inorder to close this gap, Lyssa uses the plugin mechanism that makes itpossible to analyze the XML template before it is translated. Withreference to the equation example, the author be able to choose theprocedure for equation processing. Course Processing For the transformation process of the COB packages, it is necessaryto analyze their structure. They consist of a set of physical resourcefiles and a special file called manifest. It stores the course structureand handles the connection between structure and content files. Theseconnections are declared as resource entries in the content package anddefine the type of the resource. Inside a COB package _ remember thatCOBs can be nested with other COBs and LOBs _ type attributes are usedto distinguish between four types of resources described as follows: * Web content: the webcontent attribute indicates ordinary HTML,JPEG JPEGin full Joint Photographic Experts GroupStandard computer file format for storing graphic images in a compressed form for general use. JPEG images are compressed using a mathematical algorithm. , or MPEG (Moving Pictures Experts Group) An ISO/ITU standard for compressing digital video. Pronounced "em-peg," it is the universal standard for digital terrestrial, cable and satellite TV, DVDs and digital video recorders (DVRs). files. * Template: indicates XML data storing style-independent content. * LOB: the LOB type indicates an LOB package that is equivalent toa brick in the construction kit metaphor. * COB: the COB attribute indicates a COB package that is storedinside a package. To tranform a COB package, the resource entries must be analyzedand, depending on their content type, an action must be chosen. If a Webcontent resource is found, it will be copied to the transformed course.If an XML resource XRC, or XML Resource, is a cross-platform XML-based user interface markup language used by wxWidgets. XRC allows graphical user interface elements, such as dialogs, menu bars and toolbars, to be stored as XML, which can be loaded into the application at run-time or is found, a transformer transformer,electrical device used to transfer an alternating current or voltage from one electric circuit to another by means of electromagnetic induction. is used to convert thecontent. In the case of a COB or an LOB resource, the analysis processmust be repeated recursively. For a common course, it is sufficient tomerge the structure and the resources of each COB and LOB package intoone course. Figure 6 illustrates an example of nested COBs and LOBs. COBA determines a course structure consisting of two sections andencapsulates LOB 1 and COB B. Both section 1 and section 2 hold areference to an associated package. LOB 1 represents a brick consistingof an XML-document and an image. In contrast, COB B resembles a modelcontaining another package labelled LOB 2 albeit only one section. LOB 2itself represents a brick that contains only one XML document. Lyssa After the conceptual description of the tools required in thedevelopment process, this section presents their implementation. Asmentioned above, the tools are combined in one application called Lyssathat offers a wide range of operations to work with bricks andaggregations. In most cases, users will interact with the graphical userinterface graphical user interface (GUI)Computer display format that allows the user to select commands, call up files, start programs, and do other routine tasks by using a mouse to point to pictorial symbols (icons) or lists of menu choices on the screen as opposed to having to (GUI (Graphical User Interface) A graphics-based user interface that incorporates movable windows, icons and a mouse. The ability to resize application windows and change style and size of fonts are the significant advantages of a GUI vs. a character-based interface. ); a mode for batch operations Some action performed on a group of items at one time. See batch processing. is also provided. The GUImode is very intuitive, and many tasks can be performed bydrag'n'drop. Views are one of the main concepts concerningthis mode. A view is a certain window showing all values and operationsa task requires. The details of a view can be extended or reduced sothat only the important informations is shown. It is possible to get acomplete standard compatible package by selecting only a few files. Moreextended views allow more sophisticated operations so that experts seean application offering access to all elements and attributes of presente-learning standards. The batch mode supports the work with repeatingtasks. It allows the execution of scripts written in Python Python, in Greek mythologyPython,in Greek mythology, a huge serpent. In some myths the infant Apollo slew Python at the oracle of Gaea in Delphi; in others Apollo killed the serpent in order to claim the oracle for himself. (an objectoriented See object technology and object-oriented programming. script language See scripting language. ) and does not need the GUI. This offers the useof Lyssa in several use-cases. Figure 7 illustrates the GUI mode afterLyssa has been started. The window is divided into three parts: theworkbench on the left, the desktop on the right, and the tool bar ontop. The workbench supports the whole file handling and is the placewhere the bricks and models are stored. In normal cases, the workbenchcontains the four directory entries Courses, Learning Objects, My Homeand System. My Home is mounted to the user's home directory andSystem allows viewing of the drives in the user's operating system operating system (OS)Software that controls the operation of a computer, directs the input and output of data, keeps track of files, and controls the processing of computer programs. (e.g., A;, C: for Windows and/for Linux). [FIGURE 6 OMITTED] The mount mechanism is a special feature that allows the mountingof zipped files See ZIP file. , Windows shares, and several network file systems.Cooperating authors can share their bricks and models over the networkwithout seeing a difference. All they have to do is remount re��mount?tr.v. re��mount��ed, re��mount��ing, re��mounts1. To mount again.2. To supply with a fresh horse.n.A fresh horse.Noun 1. the folders,courses, and LOBs to the desired network file systems. Another benefit of the mount mechanism is the transparency whiletraversing tra��verse?v. tra��versed, tra��vers��ing, tra��vers��esv.tr.1. To travel or pass across, over, or through.2. To move to and fro over; cross and recross.3. inside models. An opened model does not appear as severalseparate bricks but as a seamless structure. Lyssa automatically mountsall descending descending/des��cend��ing/ (de-send��ing) extending inferiorly. bricks and a model acts Statutes and court rules drafted by the American Law Institute (ALI), the American Bar Association (ABA), the Commissioners on Uniform Laws, and other organizations. State legislatures may adopt model acts in whole or in part, or they may modify them to fit their needs. independently of the depth as onestructure. This behavior makes work easier, particularly maintenance andextension tasks. Operations on all files are called either by a right mouse click onthe tool bar or the menu bar. The pop up window of a right mouse clickis context-dependent and contains all commands for one file. The menubar contains many important commands, although not all of them. The toolbar only offers operations that are used frequently. Most of theoperations open a new window on the desktop. This behavior facilitatesthe system's use, particularly maintenance and window controltasks. Views As mentioned above, Lyssa offers different detailed views of thework with its bricks and models. This supports an efficient workstyle,and at the detail level of bricks and models, no influence of thestandards is sensitive. It is also possible to edit standard files ofother systems including all detailed elements and attributes. Incontrast to other products, Lyssa does support features like recursivemanifests and multiple organizations. [FIGURE 7 OMITTED] Window a) in Figure 8 illustrates the view of the work with bricks.This view consists of a file browser See file browsing. , making it possible to store everyfile desired in the brick and a start file selector (programming) selector - 1. In Smalltalk or Objective C, the syntax of a message which selects a particular method in the target object.2. An operation that returns the state of an object but does not alter that state. . Each brick has itsown file system that can be navigated by clicking on folders, files, andthe Folder In a graphical user interface (GUI), a simulated file folder that holds data, applications and other folders. Folders were introduced on the Xerox Star, then popularized on the Macintosh and later adapted to Windows and Unix. In Unix and Linux, as well as DOS and Windows 3. Up, New Folder, and Top buttons. However, the"navigation to" files stored in the file system cannot beaccessed. Therefore, the drag'n'drop feature for moving orcopying files from one brick to another, as well as from other filesystems, is available. Specific file formats like the XML source filecan be added to a brick with a context menu. One file must be declaredas the entry point of this brick. This means that the file chosen by the Start File selector will beidentified as the file containing the content of this brick. In thisexample, it is the export.xml file referring to an image labelledexport.jpg. The brick view hides the complex features proposed by theIMS content packaging specification and presents only the functionalityrequired for the production of bricks. If a file is dragged from theworkbench and dropped on the file viewer Software that displays the contents of a file. File viewers are a quick way of looking into different types of files without having to open each application that created them. A general purpose file viewer is capable of displaying a wide variety of document, database, spreadsheet and , all values required by thestandard will be set automatically. In the case of the export.jpg image,the type value of the IMS content package is set to webcontent. Incontrast, in the case of the document.xml file, the type value templatedenotes the brick for a later translation process by the framework. Models are edited with a view as illustrated in Figure 8, windowb). The organization or course structure is shown in the upper tree.Models can be built with several bricks shown in the lower tableassociated with one or more items. To offer a convenient composing com��pose?v. com��posed, com��pos��ing, com��pos��esv.tr.1. To make up the constituent parts of; constitute or form: process, Lyssa allows dragging bricks and models from the workbench orout of other models and droping them into the tree widget Pronounced "wih-jit," for decades, the term has been a popular word for a generic "thing" when there is no real name for it. It is often used to describe examples of made-up products along with other fictitious names; for example, "10 widgets, 5 frabbits and 2 dingits. . A new itemwith reference to the brick or model will be added, and only its nameremains to be specified. Figure 9 illustrates the fully supported viewof the IMS content packaging specification. First of all, a modelcontains one or more organizations. An organization describes thestructure and the navigation for the included content. In this example,the model has two organizations Organization00 and Organization01. Atree is used to arrange the items for a course about design patterns (asoftware engineering technique). An item resembles a reference to abrick with a specific title. The root node (mathematics, data) root node - In a tree, a node with no parents, but which typically has daughters. of the tree, for example,references brick Brick00 and is titled Design Patterns. [FIGURE 8 OMITTED] There are two ways to create these items: Either a brick is droppedonto the tree, or the command New Item from the context menu is chosenby a right mouse click on an existing item. All references and titles can be changed by a double click. This isbecause existing standards do not arrange different resource types suchas brick and model. Hence, bricks and models are saved in the sameformat for content packages, e.g., IMS content package or SCORM. Eachcontent package contains the used files, which are shown in the lefttree. The Manifest tab next to the File tab switches to the manifeststructure. A manifest can contain other manifests, but this is a specialfeature and is rarely used. [FIGURE 9 OMITTED] Export Lyssa comes with an export feature supporting the publishingprocess (illustrated in Figure 10). With the export window, an authordetermines the course that has to be translated. In the settings area,the transformation package responsible for the generated output formatand layout must be chosen. The table contains the active and non-activeprocessors required by the processing framework for modifying XMLcontent. The output field contains the output directory or file, whichstores the translated course ready for import into an LMS. After all necessary settings have been determined, the translationprocess can be started by pushing the export button. By doing so,information about the translation process is written into the messagearea. If errors (e.g., XML parser Software that reads an XML document, identifies all the XML tags and passes the data to the application. See XML processor. errors) occur during thetransformation process, they will be shown in the message field. As mentioned above, the information about generating the outputformat is stored in the transformation package separately. Themodification of these settings is only necessary if a new format isdeveloped or its layout is to be modified. For this purpose, anadditional tool is available for browsing the resources, setting up thepackage, and modifying the transformers. The Construction-Kit Server (CKS) The CKS is an important aspect of the construction kit metaphor;this allows users to share COB and LOB files with other users whiledeveloping them. The server supports several access possibilities, likeWeb browsers The following is a list of web browsers. HistoricalHistorically important browsersIn order of release: WorldWideWeb, February 26, 1991 Erwise, April 1992 ViolaWWW, May 1992, see Erwise , Windows Explorer See Explorer. , or Lyssa itself. With Lyssa, it ispossible to establish a connection to the server, select an LOB or COBfile of interest, and open it directly with the authoring client. Thiscan be done since Lyssa implements the WebDAV (Network Working Group,1999) protocol, which is also provided by the CKS. Therefore, anyapplications implementing the WebDAV API (Application Programming Interface) A language and message format used by an application program to communicate with the operating system or some other control program such as a database management system (DBMS) or communications protocol. are capable of accessing thefiles stored in the CKS. [FIGURE 10 OMITTED] An important aspect of the server is the locking support. When abrick is opened by a content developer, no other user is able to openit. The file will be unlocked after all necessary changes are made andthe brick is saved. This mechanism handles the file communication andensures that no data will be lost. Another benefit of the CKS is thateach file has a version property, allowing a developer to access anearlier version of the brick. This is of special importance in acooperative work environment. EXAMPLE COB This section presents an example introducing the developmentprocess of bricks and models. The first step in creating reusablelearning material is to determine its granularity. The content should beverbalized coherently, and independently of other modules. This meansthat there should be no reference to an LOB, which is not part ofitself. Where there is a dependency that cannot be resolved, the LOBmust be aggregated with a superior COB or model to preserve itsreusability The ability to use all or the greater part of the same programming code or system design in another application. reusability - reuse . Next, the example deals with the topic of complex numbers (Thiere,Padberg, & Oeve, 2003). A reusable COB that explains the foundationsof complex numbers should be developed. Such a COB can be integratedinto various technical course materials, like mathematics for mechanicalengineering or mathematics for computer science. One aspect of thecomplex numbers deals with the topic Euler formula and polar coordinates 1. Coordinates derived from the distance and angular measurements from a fixed point (pole).2. In artillery and naval gunfire support, the direction, distance, and vertical correction from the observer/spotter position to the target. illustrated in Figure 11. Bricks can be coded with the brick modeling language MathkitML.Several tags such as paragraph, itemize To individually state each item or article.Frequently used in tax accounting, an itemized account or claim separately lists amounts that add up to the final sum of the total account on claim. , or table are available toformulate learning content. However, the document processing frameworkprovides a mapping mechanism that offers the possibility of readingother document formats as well. With the brick view of Lyssa, the XML file can be created andcoded. The result is an LOB file containing both the XML file and IMSmanifest. Next, the LOB file must be referenced by the item, Eulerformula and polar coordinates, within the model view, as illustrated inFigure 12. It shows the structure of the foundation course labeledbasics.cob. The items of the course structure referencing a set ofbricks are arrangeable in several ways. The COB produced has a coarse granularity and can be integratedinto lectures or online presentations for self-study access. There areseveral possible combinations with other COBs. Examples includemotivation, general or specific exercises, exploration environment, orextra information. If the course will be used by students forself-study, a basics object must be combined with the exercise orexploration COB. In contrast, the motivation COB can be used inlectures. Figure 13 illustrates the lecture course rendered in HTML. [FIGURE 12 OMITTED] [FIGURE 13 OMITTED] The navigation on the left was generated recursively with themanifest of the bricks and models. For the integration of the courseinto an LMS, a manifest file representing the course is also available. A transformation package can be utilized to render a PDF in orderto obtain a format that is more usable for presentation in lectures orfor printing purposes. In the case of the PDF format, the transformation package maps thecourse structure defined in the manifest files to bookmark A stored location for quick retrieval at a later date. Web browsers provide bookmarks that contain the addresses (URLs) of favorite sites. Most electronic references, large text databases and help systems provide bookmarks that mark a location users want to revisit in the future. entries, asillustrated in Figure 14. It should be mentioned that the use offeatures like Java-Script within a PDF is also possible. Lyssa takesadvantage of the link and Java-Script support provided by the PDFformat. This enables the use buttons and links to reference applets. Inaddition, it makes it possible to generate quizzes. CONCLUSION This article has presented the architecture and the implementationof the authoring system Lyssa. It supports lecturers in the developmentprocess and enables the reuse of existing LOBs with the goal of creatinguniform courses. In contrast to other authoring systems such asAuthorware, Lyssa provides a mechanism for the semantic definition ofgranular granular/gran��u��lar/ (gran��u-lar) made up of or marked by presence of granules or grains. gran��u��laradj.1. Composed or appearing to be composed of granules or grains.2. LOBs, which can be integrated seamlessly into any coursestructure. Using the construction kit server, many authors are able toshare semantic LOBs without modifiying them for presentation. Theexample of complex numbers has shown that content developers can worktogether effectively and use the foundation object Euler formula andpolar coordinates in several higher courses such as mathematics forengineers and technical computer science. [FIGURE 14 OMITTED] The architecture is based on the construction kit metaphor fore-learning systems, which gives authors and developers a common view ofmodular course design and implementation. Additionally, the role concepthelps system and content developers, as well as professors and students,to associate general tasks. Summarizing our considerations, the authoring tool Lyssa bringstogether the three developer roles of brick developer, composer, andpublisher in the implementation of one single application. The conceptsof each role were discussed separately before the tool Lyssa waspresented. With Lyssa, the content developer is able to take on thedifferent roles and to perform specialized tasks. The Universities ofHamburg, Hagen, and Paderborn use Lyssa for the production of reusableCOBs, developed in the field of mathematics, computer engineering, andmechanical engineering, with remarkable success (Bauch & Unger,2003). In the future, improved support of meta data will be added,enabling the construction kit server to provide search algorithms In computer science, a search algorithm, broadly speaking, is an algorithm that takes a problem as input and returns a solution to the problem, usually after evaluating a number of possible solutions. forthe locatation of COBs and LOBs. Additionally, the server will beconnected to the document API to provide on demand presentations throughthe Web server. References ADL (2004). Sharable content object reference model (SCORM).Retrieved June 12, 2004, from http://www.adlnet.org/downloads/70.cfm Baudry, A., Bungenstock, M., & Mertsching, B. (2002a).Architecture of an e-learning system with embedded Inserted into. See embedded system. authoring support. InM. Driscoli & T. C. Reeves, E-LEARN 2002--World Conference onE-Learning in Corporate, Government, Healthcare, & Higher Education,110-116. Baudry, A., Bungenstock, M., & Mertsching, B. (2002b). 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Learning object design and sequencing theory.Doctoral dissertation dis��ser��ta��tion?n.A lengthy, formal treatise, especially one written by a candidate for the doctoral degree at a university; a thesis.dissertationNoun1. , Brigham Young University Brigham Young University,at Provo, Utah; Latter-Day Saints; coeducational; opened as an academy in 1875 and became a university in 1903. It is noted for its law and business schools. , Provo, Utah. Wollowski, M. (2002). XML based XML Base is a W3C recommendation, that proposes a facility for defining base URIs for parts of XML documents.XML Base recommendation was adopted on 2001-06-27. External linksXML Base W3C Recommendation course websites. In E-LEARN2002--World Conference on Educational in Corporate, World Conference onE-Learning in Corporate, Government, Healthcare, & Higher Education,1043-1048. Notes (1) Support by the German Federal Ministry of Education andResearch, project Math-kit (08NM084D is gratefully acknowledged. (2) The authors recently moved from Hamburg to Paderborn. (3) Named after the Greek goddess. ANDREAS BAUDRY Department of Computer Science, Germany baudry@upb.de MICHAEL BUNGENSTOCK Faculty of Computer Science, Germany bungenstock@informatik.uni-hamburg.de BAERBEL MERTSCHING Faculty of Computer Science, Germany mertsching@upb.de<?xml version="1.0" encoding="ISO-8859-1" ?><lob title="Euler formula and polar coordinates"xml:lang="en"> If one introduces the angle <formula text="true" mode="latex"> \varphi </formula> between the "vector" <formula text="true" mode="latex">z</formula> and the real axis in the Gaussian Plane, then the well-known formulas for sine and cosine yield: <formula text="false" mode="latex"> z = r\, (\cos\varphi + \imath \sin \varphi) = r \, \cos \varphi + r \, \imath \sin \varphi </formula> where we use the convention ......Figure 11. Example: XML file of the Euler brick

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