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1: <html> 2: <head> 3: <meta name=Title 4: content="Session Three: Publication, Content Maps, Course Maps (Gerd)"> 5: <meta http-equiv=Content-Type content="text/html; charset=macintosh"> 6: <title>Session Three: Publication, Content Maps, Course Maps (Gerd)</title> 7: <style> 13: </style> 14: </head> 15: <body bgcolor=#FFFFFF class="Normal" lang=EN-US> 16: <div class=Section1> 17: <h2>Session Three: Publication, Content Maps, Course Maps (Gerd)</h2> 18: <h3><a name="_Toc514840855"></a><a name="_Toc421867109">Publication of a Resource</a></h3> 19: Authors can only write-access the /~authorname/ space. They can copy resources into 23: the resource area through the publication step, and move them back through 24: a recover step. Authors do not have direct write-access to their resource 25: space. 26: <div class=Section9> 27: <div style='border:solid windowtext .5pt;padding:1.0pt 4.0pt 1.0pt 4.0pt'> 28: Construction space � Publication Step � Resource space 34: � Retrieve � 37: 38: </div> 39: During the publication step, several events will be triggered. Metadata 40: is gathered, where a wizard manages default entries on a hierarchical per-directory 41: base: The wizard imports the metadata (including access privileges and royalty 42: information) from the most recent published resource in the current directory, 43: and if that is not available, from the next directory above, etc. The Network 44: keeps all previous versions of a resource and makes them available by an 45: explicit version number, which is inserted between the file name and extension, 46: for example foo.2.html, while 47: the most recent version does not carry a version number (foo.html). Servers subscribing to a changed 49: resource are notified that a new version is available. 50: <h3><a name="_Toc514840857"></a><a name="_Toc421867110">Content Re-usage and 51: Granularity</a></h3> 52: Any faculty participating in the Network can publish their own learning 53: resources into the common pool. To that end, the Network provides a �construction 54: space� which is only accessible to the author, and a publication process, 55: which transfers the material to the shared pool � during the publication 56: process, metadata about the resource is gathered, and system-wide update 57: notification and versioning mechanisms are triggered.. 58: Learning resources could be simple paragraphs of text, movies, applets, 59: individualizing homework problems, etc. In addition to providing a distributed 60: digital library with mechanisms to store and catalog these resources, the 61: Network enables faculty to combine and sequence these resources at several 62: levels: An instructor from Community College A could combine a text paragraph 63: from University B with a movie from College C and an online homework problem 64: from Publisher D, to form one page. Another instructor from High School 65: E can take that page from Community College A and combine it with other 66: pages into a module, unit or chapter. Those in turn can be combined into 67: whole coursepacks. Faculty can design their own curricula from existing 68: and newly created resources instead of having to buy into a complete off-the-shelf 69: product. 70: Fig. 2.3.1 shows a general overview 71: of the resource assembly mechanism and the different levels of content granularity 72: supported by the current implementation of this principle. The topmost puzzle 73: piece represents a resource at the fragment level � one GIF, one movie, 74: one paragraph of text, one problem, or one regular web page. Attached to 75: the resource is metadata gathered at the publication time of the resource. 76: Using the resource assembly tool described below, these fragments and pages 77: can be assembled into a page. A page is a resource of the grain size which 78: would be rendered as one page on the web and/or on the printer. 79: Using the same tool, fragments (which would then be rendered as standalone 80: pages), pages and sequences can be assembled into sequences. Sequences are 81: resources which are rendered a sequence of pages, not necessarily linear. 82: Examples are one lesson, one chapter, or one learning cycle 83: On the third granularity level, fragments (rendered as standalone pages), 84: pages, and sequences can be assembled into courses. Courses are a sequence 85: which represents the entirety of the resources belonging to a learning unit 86: into which learners can be enrolled. Examples are a University one-semester 87: course, a 88: workshop, or a High School class. 89: <img border=0 90: width=291 height=436 id="_x0000_i1029" src="handout_files/image005.png"> 91: Fig. 2.1.1 � Resource Assembly 93: <h3><a name="_Toc514840858"></a><a name="_Toc421867111">Maps</a></h3> 94: To increase the utility of the materials, the number of hard-coded hyperlinks 95: between the resources should be minimized. The actual combining and sequencing 96: is part of the system functionality and driven by external "roadmaps", 97: which are constructed by the instructors. With this mechanism, one and the 98: same resource can be part of different courses in different contexts. The 99: soft-linking makes it possible to import only the desired set of resources 100: without effectively importing additional parts another instructors resources 101: through hard-linked menus or "next page" buttons that might resided 102: on those resources. 103: <h3><a name="_Toc514840859"></a><a name="_Toc421867112">Curriculum Adaptivity</a></h3> 104: Maps allow for conditional choices and branching points. The actual path 105: through and presentation of the learning resources is determined by instructor-specified 106: combinations of learner choices and system-generated adaptations (for example, 107: if the learner does not pass a test, additional resources may be included). 108: Each learner can have an individualized curriculum according to preferences, 109: capabilities and skills. 110: These maps can be generated at different levels of granularity with a graphical 111: tool, or in an automated way through custom scripts. 112: <h3><a name="_Toc514840860"></a><a name="_Toc421867113">Resource Assembly 113: Tool</a></h3> 114: The Network provides the Resource Assembly Tool as one means to generate 115: maps. The Resource Assembly Tool provides a graphical user interface inside 116: of a standard web browser. The current implementation is written in JavaScript. 117: 118: Fig. 2.3.2 shows screenshots of 119: the current implementation. The interface usually consists of two browser 120: windows, one resizable one with a frameset that contains the menu and the 121: map under construction, and a multipurpose non-resizable window that displays 122: information and input forms. 123: When a new map is started, it only has a start and a finish resources. 124: The author can then enlarge the map area and insert resources into it. 125: In Fig. 2.3.2A, the author is editing 126: information about a resource in the map after clicking on the box representing 127: the resource in the map. In the dialog, the author can enter a map-internal 128: title for the resource, which is displayed to the learners when navigating 129: the maps. In the same dialog, the author will specify the URL of the resource, 130: which can either be internal to the Network, or any URL of a web page outside 131: of it. For internal resources, the author can also browse the Network filesystem 132: or search the resource metadata to locate an appropriate resource. 133: <img border=0 width=431 134: height=327 id="_x0000_i1030" src="handout_files/image006.jpg">Fig. 2.3.2A � Example, Graphical 136: User Interface of Resource Assembly Tool 137: The resource priority can be chosen. A resource can be �regular,� �mandatory� 138: or �optional.� These resource priorities are only used in book-keeping of 139: earned points by the learners. Within the map, resources of different priorities 140: are displayed in different colors. 141: The dialog also allows for two modes of removing the resource from the 142: map: deleting it from the map including every link to and from it, and deleting 143: it while reconnecting any links that went through the resource. As an example, 144: resources A and B might both connect to resource C, and resource C might 145: connect to D. When removing C from the map using the first option, A and 146: B will not be connected to D anymore. Using the second option, in the end, 147: A will connect to D, and B will connect to D. In the latter case, the Resource 148: Assembly tool will also handle link conditions correctly: if A connected 149: to C under condition 1, and C connected to D under condition 2, then in 150: the end A will connect to D under a new condition which is (1 AND 2). 151: Finally, this dialog allows the author to connect the resource to another 152: resource (or itself) through a new link. When selecting this option, the 153: Resource Assembly Tool goes into link mode, and will link the current resource 154: to the next resource clicked on (unless the action is cancelled). 155: <img border=0 width=431 height=327 id="_x0000_i1031" 156: src="handout_files/image007.jpg"> 157: Fig. 2.3.2B � Example, Graphical 159: User Interface of Resource Assembly Tool 160: Fig. 2.3.2B shows the Resource 161: Assembly Tool in info mode, that is, when no specific component of the map 162: is edited, and if the Tool is not in link mode. In info mode, the contents 163: of the dialog window change dynamically as the mouse is moved over the components 164: of the map. In this case, the mouse pointer is over the link condition between 165: two resources. The dialog window shows the titles of the connected resources, 166: as well as the condition priority. In this scenario, the condition priority 167: is set such that the link cannot be taken (�is blocked�) if the condition 168: is false. The condition priority can also be set such that the link is recommended 169: if the condition is true (possibly giving the learner several options where 170: to go next), or that the link has to be taken (�is forced�) over any other 171: possible link if the condition is true. Within the map, conditions of different 172: priorities are displayed in different colors. If the author now were to 173: click on the condition, the Tool would go into edit mode, and the condition 174: could be edited. 175: Fig. 2.3.2C shows the Tool in edit 176: mode for the link between the resource titles displayed. The author can 177: remove the link, or insert a new resource into the link. 178: Obviously, by this mechanism, rather complex maps can be generated. These 179: are different from binary trees, both because branches can loop back, and 180: because branches can be re-united � in fact, most branches re-unite in the 181: finish resources. Into each link, a condition with one of three different 182: priorities can be attached. Whether or not a certain resource in the map 183: can be displayed depends on whether or not it can be reached through any 184: path along allowed links, starting with the start resource of the course. 185: If a resource is not linked to, it is assumed to be accessible if the map 186: which it is part of is accessible. 187: <img border=0 width=431 height=327 id="_x0000_i1032" 188: src="handout_files/image008.jpg"> 189: Fig. 2.3.2C � Example, Graphical 191: User Interface of Resource Assembly Tool 192: <h3><a name="_Toc514840861"></a><a name="_Toc421867114">Map Representation 193: and Storage Format</a></h3> 194: Fig. 2.3.3 shows the XML representation 195: of the resource map constructed in Fig. 2.3.2, which is the format in which maps are stored. In 197: the figure, however, additional graphical map layout information generated 198: by the Resource Assembly Tool is not displayed. This graphical information 199: is optional to re-generate the same graphical layout when the map is brought 200: up again in the Resource Assembly Tool, and is not needed for any other 201: system functionality. 202: Maps can be generated by tools other than the Resource Assembly Tool. In 203: particular, an author might have some other representation of a course sequence, 204: which can be converted into a map using scripts. If this map then were to 205: be brought up in the Resource Assembly Tool, the Tool would automatically 206: generate a graphical layout for it. Each entry of the map (resources, conditions 207: and links) is stored in a separate tag. 208: Resources and conditions have to have unique ID numbers. These numbers 209: are automatically generated by the Resource Assembly Tool when the entry 210: is first created, or added to the entries when a map generated outside the 211: Resource Assembly Tool is first retrieved. They can also be assigned by 212: custom scripts or added in by hand. 213: In this example, Fig. 2.3.3, entry 1 is the start resource of the map � when this map is accessed, 215: the source (src) URL of this tag will be the first resource rendered. Entry 216: 2 is the finish resource of this map. This resource will be the last resource 217: in the sequence of resources. Entry 6 is a problem resource with the given 218: URL and title, as well as the priority �mandatory�. Entry 19 is a condition, 219: which is used by the link between entries 6, the problem, and 9, a sequence. 220: The final syntax for conditions has not yet been determined. 221: <table border=1 cellspacing=0 cellpadding=0> 222: <tr> 223: <td width=443 valign=top class="Normal"> 224: <map> 225: <resource id="1" 226: 227: src="/res/msu/korte/phy231welcome.html" 228: 229: type="start" 230: 231: title="Start"></resource> 232: <resource id="2" 233: 234: src="" 235: type="finish" 236: title="Finish"></resource> 237: <resource id="6" 238: 239: src="/res/msu/korte/tests/units.problem" 240: 241: type="mandatory" 242: 243: title="Physical 244: Units Test"></resource> 245: <resource id="9" 246: 247: src="/res/msu/korte/chapters/onedim.sequence" 248: 249: title="Motion 250: in One Dimension"></resource> 251: <resource id="11" 252: 253: src="/res/msu/bauer/bridges/units.sequence" 254: 255: title="Physical 256: Units Refresher"></resource> 257: <condition id="19" 258: 259: type="stop" 260: 261: value="user.assessments[this./res/msu/korte/tests/units.problem].status=solved"> 262: </condition> 263: <link from="1" 264: to="6"></link> 265: <link from="6" 266: to="9" condition="19"></link> 267: <link from="6" 268: to="11"></link> 269: <link from="11" 270: to="6"></link> 271: </map> 272: </td> 273: </tr> 274: </table> 275: Fig. 2.3.3 � XML representation of the map in Fig. 2.3.2C (non-graphical 277: information only). 278: <h3><a name="_Toc514840866"></a><a name="_Toc514840862"></a><a 279: name="_Toc514920452"></a><a name="_Toc421867115">Example of Nested Maps</a></h3> 280: Fig. 2.3.4 shows the XML representation 281: of three maps which are imported into each other. Fig. 2.3.4B 282: is the sequence that is referenced as resource 9 in the course map Fig. 283: 2.3.4A. In the resulting map, the entry point of resource 285: 9 in Fig. 2.3.4A is in fact 286: the entry point of the start resource of Fig. 2.3.4B, namely, resource 1 there. The exit point of resource 288: 9 in Fig. 2.3.4A is the exit 289: point of the finish resource of Fig. 2.3.4B, namely, resource 2 there. 291: Fig. 2.3.4C is the page which is 292: referenced as resource 24 in Fig. 2.3.4B. 294: A course can easily contain several hundreds of these nested maps. Since 295: the accessibility of each individual resource in the course depends on the 296: state of all possible paths linking it to the start resource of the course 297: across all intermediate maps, the computation and disk-I/O effort per single 298: transaction could quickly become prohibitive. Thus, all maps and conditions 299: are compiled into a pre-processed binary data structure at the start of 300: a session. 301: <table border=1 cellspacing=0 cellpadding=0> 302: <tr> 303: <td width=442 valign=top class="Normal"> 304: <map> 305: <resource id="1" 306: src="" type="start" title="Start"></resource> 307: <resource id="2" 308: src="" type="finish" title="Finish"></resource> 309: <resource id="5" 310: src="/res/msu/korte/tests/pretest.problem" type="mandatory" 311: 312: title="Pretest"></resource> 313: <resource id="9" 314: src="/res/msu/korte/parts/part1.sequence" type="mandatory" 315: 316: title="Part 317: 1"></resource> 318: <resource id="11" 319: src="/res/msu/korte/tests/midterm.sequence" type="mandatory" 320: 321: title="Midterm"></resource> 322: <resource id="15" 323: src="/res/msu/korte/parts/part2.sequence" type="mandatory" 324: 325: title="Part 326: 2"></resource> 327: <condition id="19" 328: type="stop" 329: value="user.assessments[this./msu/korte/tests/pretest.problem].status=solved"> 330: </condition> 331: <resource id="20" 332: src="/res/msu/korte/refresh/refresher.sequence" 333: title="Refresher"></resource> 334: <resource id="29" 335: src="/res/msu/korte/tests/final.sequence" type="mandatory" 336: 337: title="Final 338: Exam"></resource> 339: <condition id="30" 340: type="stop" 341: value="user.assessments[this./msu/korte/tests/midterm.sequence].percent>60"> 342: </condition> 343: <resource id="36" 344: src="/res/msu/korte/refresh/review.sequence" 345: title="Review"></resource> 346: <condition id="43" 347: type="force" 348: value="user.assessments[this./msu/korte/tests/midterm.sequence].percent<10"> 349: </condition> 350: <resource id="58" 351: src="/res/msu/korte/chapters/applications.sequence" type="optional" 352: 353: title="Applications"></resource> 354: <condition id="70" 355: type="stop" 356: value="user.assessments[this./msu/korte/tests/final.sequence].percent>60"> 357: </condition> 358: <link from="1" 359: to="5"></link> 360: <link from="9" 361: to="11"></link> 362: <link from="11" 363: to="15" condition="30"></link> 364: <link from="5" 365: to="9" condition="19"></link> 366: <link from="5" 367: to="20"></link> 368: <link from="20" 369: to="5"></link> 370: <link from="11" 371: to="36" condition="43"></link> 372: <link from="36" 373: to="9"></link> 374: <link from="36" 375: to="11"></link> 376: <link from="15" 377: to="29"></link> 378: <link from="29" 379: to="2" condition="70"></link> 380: <link from="11" 381: to="11"></link> 382: </map> 383: </td> 384: </tr> 385: </table> 386: Fig. 2.3.4A � Example of a course map that has nested sequences 388: 390: <table border=1 cellspacing=0 cellpadding=0> 391: <tr> 392: <td width=442 valign=top class="Normal"> 393: <map> 394: <resource id="1" 395: src="" type="start" title="Start"></resource> 396: <resource id="2" 397: src="" type="finish" title="Finish"></resource> 398: <resource id="5" 399: src="/res/msu/korte/parts/part1intro.html" 400: title="Part 401: 1 Introduction"></resource> 402: <resource id="6" 403: src="/res/msu/korte/parts/part1dir.xml" title="Directions"></resource> 404: <resource id="12" 405: src="/res/msu/korte/tests/part11.problem" title="Problem 406: 1"></resource> 407: <resource id="13" 408: src="/res/msu/korte/tests/part13.problem" title="Problem 409: 3"></resource> 410: <resource id="19" 411: src="/res/msu/korte/tests/part12.problem" title="Problem 412: 2"></resource> 413: <resource id="24" 414: src="/res/msu/korte/parts/summary.page" title="Summary"></resource> 415: <condition id="47" 416: type="stop" 417: value="user.assessments[this./msu/korte/tests/part11.problem].status=solved"> 418: </condition> 419: <condition id="48" 420: type="stop" 421: value="user.assessments[this./msu/korte/tests/part12.problem].status=solved"> 422: </condition> 423: <condition id="49" 424: type="stop" 425: value="user.assessments[this./msu/korte/tests/part13.problem].status=solved"> 426: </condition> 427: <link from="5" 428: to="6"></link> 429: <link from="1" 430: to="5"></link> 431: <link from="6" 432: to="12"></link> 433: <link from="6" 434: to="13"></link> 435: <link from="6" 436: to="19"></link> 437: <link from="12" 438: to="24" condition="47"></link> 439: <link from="19" 440: to="24" condition="48"></link> 441: <link from="13" 442: to="24" condition="49"></link> 443: <link from="24" 444: to="2"></link> 445: </map> 446: </td> 447: </tr> 448: </table> 449: Fig. 2.3.4B � Example of a sequence (part1.sequence) that has nested pages 453: <table border=1 cellspacing=0 cellpadding=0> 454: <tr> 455: <td width=443 valign=top class="Normal"> 456: <map> 457: <resource id="1" 458: src="" type="start" title="Start"></resource> 459: <resource id="2" 460: src="" type="finish" title="Finish"></resource> 461: <resource id="5" 462: src="/res/msu/smith/racecar.problem"></resource> 463: <resource id="6" 464: src="/res/msu/smith/toofast.html"></resource> 465: <resource id="8" 466: src="/res/msu/smith/tooslow.html"></resource> 467: <resource id="15" 468: src="/res/msu/smith/accelerate.html"></resource> 469: <condition id="40" 470: type="force" 471: value="user.assessments[this./msu/smith/racecar.problem].status=solved"></condition> 472: <condition id="41" 473: type="stop" 474: value="user.assessments[this./msu/smith/racecar.problem].answer=friction"></condition> 475: <condition id="42" 476: type="stop" 477: value="user.assessments[this./msu/smith/racecar.problem].answer=sliding"></condition> 478: <condition id="43" 479: type="stop" 480: value="user.assessments[this./msu/smith/racecar.problem].answer=nonconstant"></condition> 481: <link from="1" 482: to="5"></link> 483: <link from="5" 484: to="6" condition="41"></link> 485: <link from="5" 486: to="8" condition="42"></link> 487: <link from="5" 488: to="15" condition="43"></link> 489: <link from="6" 490: to="2"></link> 491: <link from="8" 492: to="2"></link> 493: <link from="15" 494: to="2"></link> 495: <link from="5" 496: to="2" condition="40"></link> 497: </map> 498: </td> 499: </tr> 500: </table> 501: Fig. 2.3.4C � Example of a page (summary.page) 505: 507: <img border=0 width=432 508: height=456 id="_x0000_i1033" src="handout_files/image009.jpg"> 509: Fig. 2.3.5 � Flow chart of the course initialization routine run when 511: a learner first accesses a course during a session (see Figs. 2.1.6A and 512: 2.1.8A for the procedures loadmap and traceroute) 516: <h3><a name="_Toc514840863"></a><a name="_Toc514920453"></a><a 517: name="_Toc421867116">Initialization of a Course for a Learner</a></h3> 518: When a learner first enters a course during a session, the system will 519: initialize this course for the learner. In particular, at this point, the 520: course map and all nested (embedded) maps and resources are evaluated, and 521: the information is compiled into two binary structures, which are stored 522: with the session information: the resource properties hash, and the link 523: conditions array. This information will be used over the duration of the 524: session for several purposes: navigation (which resource is the next, which 525: one the previous?), for access control (can the resource be reached under 526: the link conditions given the current state of the student?), and to register 527: assessment results within the context of a certain course and map (there 528: might be several instances of the same problem resource within a course). 529: <h3><a name="_Toc514840864"></a><a name="_Toc514920454"></a><a 530: name="_Toc421867117">Evaluation of the Map Structure for a Course</a></h3> 531: The URL of the course is passed to the procedure readmap (Fig. 2.3.5). Procedure readmap 534: first initializes the resource properties as an empty hash, seeds the link 535: conditions array with a 0th element, which is set to �true�, 536: priority �normal�, and sets the map counter to 0 (Fig. 2.3.5, Step R1). While the resource properties hash, the link conditions 538: array and the map counter are global variable of the initialization process, 539: all other variables are local to the procedures (an important property for 540: these routines to run recursively). The procedure readmap then calls procedure loadmap for the URL of the course (Fig. 543: 2.3.5, Step R2). 544: Figs. 2.1.6, 2.1.7 show a dump 545: of excerpts of the binary structure generated in loadmap for the nested maps of example 547: Fig. 2.3.4. 548: Procedure loadmap (Fig. 549: 2.3.6A) first checks if the map URL 550: has already been processed (multiple inclusion of the same map in a course 551: structure) (Fig. 2.3.6A, Step L1) 552: � if it was, it has been assigned a map counter value in the resource properties 553: hash. If the map has been processed, there is no need to process it again, 554: and loadmap returns. 555: If the map has not been processed yet, the map counter is incremented and 556: the map is registered under the current value in the resource properties 557: hash (Fig. 2.3.6A, Step L2). The 558: file is then opened (Fig. 2.3.6A, Step L3), which might entail prior replication, and the contents 560: are parsed. If there are no further entries, loadmap returns (Fig. 2.3.6A, Step 562: L4). 563: The new entry tag is then read (Fig. 2.3.6A, Step L5) and the type is determined (Fig. 2.3.6A, 565: Step L6). 566: If the entry is a resource (Step L7), a resource ID is formed by combining the map counter 568: and the resource ID within the map. For example, the �Part I Introduction� 569: resource of part1.sequence (Fig. 2.3.4B) was assigned the resource ID 2.5, since it has the 571: internal resource ID 5 in the 2nd map processed (see Fig. 572: 2.3.6B under �ids_�). If the same URL 573: is found again, additional IDs are assigned to it. It is necessary to store 574: the IDs under the URL in the resource properties hash for reverse lookup 575: if a user simply requests a URL. If the resource is a start or finish resources, 576: the resource ID is registered as the start or finish resource of the map, 577: respectively (Fig. 2.3.6B, 578: �map_start_�, �map_finish_�). The properties of the resource (URL, Title, 579: Priority, etc) are now stored under the resource ID, see for example Fig. 580: 2.3.6B �title_2.5�. 582: If the resource is not a map itself (Fig. 2.3.6A, Step L8), the next entry is read. Otherwise, procedure loadmap calls itself recursively to process 586: that map (Step L9). 587: If in Step L6, the type of the 588: entry was determined to be a condition, a condition ID is formed (Step 589: L10) by again combining the map counter 590: with the internal ID. The condition is also added to the end of the condition 591: array (see Fig. 10), which 592: is a compilation of all conditions in the course (Step L11). The conditions in this array are evaluated when 594: a transaction occurs that could change the state of the student, and the 595: state of each condition is stored by the index number in the session environment. 596: A reference to the index number in the condition array is stored under the 597: condition ID (Fig. 2.3.6D, 598: �condid_�). 599: If the entry is a link (Step L6), a link ID is generated (Step L12). This ID is formed by combining the map counter and 602: another counter which is incremented for every new link within the map. 603: Under this ID, the IDs of the originating and the destination resource of 604: the link are stored, as well as that of the link condition (Fig. 605: 2.3.6D). For the originating resource, in Step 607: L13 the link ID is added to the list 608: of outgoing links (Fig. 2.3.6C, 609: �to_�), and for the destination resource, the link ID is added to the list 610: of incoming links (Fig. 2.3.6C, 611: �from_�). 612: After the last entry has been processed, procedure loadmap returns. After the last map has 614: been processed, the original course-level instance of loadmap returns to readmap (Fig. 2.3.5, Step R2). 619: <img border=0 width=432 height=547 id="_x0000_i1034" 620: src="handout_files/image010.jpg"> 621: Fig. 2.3.6A � Flow chart of procedure loadmap 624: 626: <table border=1 cellspacing=0 cellpadding=0> 627: <tr> 628: <td width=443 valign=top class="Normal"> 629: ids_/res/msu/korte/chapters/applications.sequence: 631: 1.58 632: ids_/res/msu/korte/parts/part1.sequence: 1.9 634: ids_/res/msu/korte/parts/part1dir.xml: 2.6 636: ids_/res/msu/korte/parts/part1intro.html: 2.5 638: ids_/res/msu/korte/parts/part2.sequence: 1.15 640: ids_/res/msu/korte/parts/summary.page: 2.24 642: ids_/res/msu/korte/refresh/refresher.sequence: 1.20 644: ids_/res/msu/korte/refresh/review.sequence: 1.36 646: ids_/res/msu/korte/tests/final.sequence: 1.29 648: ids_/res/msu/korte/tests/midterm.sequence: 1.11 650: ids_/res/msu/korte/tests/part11.problem: 2.12 652: ids_/res/msu/korte/tests/part12.problem: 2.19 654: ids_/res/msu/korte/tests/part13.problem: 2.13 656: ids_/res/msu/korte/tests/pretest.problem: 1.5 658: ids_/res/msu/smith/accelerate.html: 3.15 660: ids_/res/msu/smith/racecar.problem: 3.5 662: ids_/res/msu/smith/toofast.html: 3.6 664: ids_/res/msu/smith/tooslow.html: 3.8 666: � 668: map_start_/res/msu/korte/foo.sequence: 1.1 670: map_start_/res/msu/korte/parts/part1.sequence: 2.1 672: map_start_/res/msu/korte/parts/summary.page: 3.1 674: � 676: map_finish_/res/msu/korte/foo.sequence: 1.2 678: map_finish_/res/msu/korte/parts/part1.sequence: 2.2 680: map_finish_/res/msu/korte/parts/summary.page: 3.2 682: � 684: title_1.11: Midterm 686: title_1.15: Part 2 688: title_1.20: Refresher 690: title_1.29: Final Exam 692: title_1.36: Review 694: title_1.5: Pretest 696: title_1.58: Applications 698: title_1.9: Part 1 700: title_2.12: Problem 1 702: title_2.13: Problem 3 704: title_2.19: Problem 2 706: title_2.24: Summary 708: title_2.5: Part 1 Introduction 710: title_2.6: Directions 712: � 714: </td> 715: </tr> 716: </table> 717: Fig. 2.3.6B � Dump of the resource properties hash. Excerpt of the 719: resource properties gathered in procedure loadmap 721: <table border=1 cellspacing=0 cellpadding=0> 722: <tr> 723: <td width=443 valign=top class="Normal"> 724: to_1.1: 1.1 726: to_1.11: 1.3,1.7,1.12 728: to_1.15: 1.10 730: to_1.20: 1.6 732: to_1.29: 1.11 734: to_1.36: 1.8,1.9 736: to_1.5: 1.4,1.5 738: to_1.9: 1.2 740: to_2.1: 2.2 742: to_2.12: 2.6 744: to_2.13: 2.8 746: to_2.19: 2.7 748: to_2.24: 2.9 750: to_2.5: 2.1 752: to_2.6: 2.3,2.4,2.5 754: to_3.1: 3.1 756: to_3.15: 3.7 758: to_3.5: 3.2,3.3,3.4,3.8 760: to_3.6: 3.5 762: to_3.8: 3.6 764: � 766: from_1.11: 1.2,1.9,1.12 768: from_1.15: 1.3 770: from_1.2: 1.11 772: from_1.20: 1.5 774: from_1.29: 1.10 776: from_1.36: 1.7 778: from_1.5: 1.1,1.6 780: from_1.9: 1.4,1.8 782: from_2.12: 2.3 784: from_2.13: 2.4 786: from_2.19: 2.5 788: from_2.2: 2.9 790: from_2.24: 2.6,2.7,2.8 792: from_2.5: 2.2 794: from_2.6: 2.1 796: from_3.15: 3.4 798: from_3.2: 3.5,3.6,3.7,3.8 800: from_3.5: 3.1 802: from_3.6: 3.2 804: from_3.8: 3.3 806: � 808: </td> 809: </tr> 810: </table> 811: Fig. 2.3.6C � Dump of the resource properties hash. Excerpt of information 813: gathered about links between resources in subroutine loadmap. 816: <table border=1 cellspacing=0 cellpadding=0> 817: <tr> 818: <td width=148 valign=top class="Normal"> 819: goesto_1.1: 1.5 821: goesto_1.10: 1.29 823: goesto_1.11: 1.2 825: goesto_1.12: 1.11 827: goesto_1.2: 1.11 829: goesto_1.3: 1.15 831: goesto_1.4: 1.9 833: goesto_1.5: 1.20 835: goesto_1.6: 1.5 837: goesto_1.7: 1.36 839: goesto_1.8: 1.9 841: goesto_1.9: 1.11 843: goesto_2.1: 2.6 845: goesto_2.2: 2.5 847: goesto_2.3: 2.12 849: goesto_2.4: 2.13 851: goesto_2.5: 2.19 853: goesto_2.6: 2.24 855: goesto_2.7: 2.24 857: goesto_2.8: 2.24 859: goesto_2.9: 2.2 861: goesto_3.1: 3.5 863: goesto_3.2: 3.6 865: goesto_3.3: 3.8 867: goesto_3.4: 3.15 869: goesto_3.5: 3.2 871: goesto_3.6: 3.2 873: goesto_3.7: 3.2 875: goesto_3.8: 3.2 877: � 879: </td> 880: <td width=148 valign=top class="Normal"> 881: comesfrom_1.1: 1.1 883: comesfrom_1.10: 1.15 885: comesfrom_1.11: 1.29 887: comesfrom_1.12: 1.11 889: comesfrom_1.2: 1.9 891: comesfrom_1.3: 1.11 893: comesfrom_1.4: 1.5 895: comesfrom_1.5: 1.5 897: comesfrom_1.6: 1.20 899: comesfrom_1.7: 1.11 901: comesfrom_1.8: 1.36 903: comesfrom_1.9: 1.36 905: comesfrom_2.1: 2.5 907: comesfrom_2.2: 2.1 909: comesfrom_2.3: 2.6 911: comesfrom_2.4: 2.6 913: comesfrom_2.5: 2.6 915: comesfrom_2.6: 2.12 917: comesfrom_2.7: 2.19 919: comesfrom_2.8: 2.13 921: comesfrom_2.9: 2.24 923: comesfrom_3.1: 3.1 925: comesfrom_3.2: 3.5 927: comesfrom_3.3: 3.5 929: comesfrom_3.4: 3.5 931: comesfrom_3.5: 3.6 933: comesfrom_3.6: 3.8 935: comesfrom_3.7: 3.15 937: comesfrom_3.8: 3.5 939: � 941: </td> 942: <td width=148 valign=top class="Normal"> 943: undercond_1.1: 0 945: undercond_1.10: 0 947: undercond_1.11: 1.70 949: undercond_1.12: 0 951: undercond_1.2: 0 953: undercond_1.3: 1.30 955: undercond_1.4: 1.19 957: undercond_1.5: 0 959: undercond_1.6: 0 961: undercond_1.7: 1.43 963: undercond_1.8: 0 965: undercond_1.9: 0 967: undercond_2.1: 0 969: undercond_2.2: 0 971: undercond_2.3: 0 973: undercond_2.4: 0 975: undercond_2.5: 0 977: undercond_2.6: 2.47 979: undercond_2.7: 2.48 981: undercond_2.8: 2.49 983: undercond_2.9: 0 985: undercond_3.1: 0 987: undercond_3.2: 3.41 989: undercond_3.3: 3.42 991: undercond_3.4: 3.43 993: undercond_3.5: 0 995: undercond_3.6: 0 997: undercond_3.7: 0 999: undercond_3.8: 3.40 1001: � 1003: condid_1.19: 8 1005: condid_1.30: 9 1007: condid_1.43: 10 1009: condid_1.70: 11 1011: condid_2.47: 5 1013: condid_2.48: 6 1015: condid_2.49: 7 1017: condid_3.40: 1 1019: condid_3.41: 2 1021: condid_3.42: 3 1023: condid_3.43: 4 1025: � 1027: </td> 1028: </tr> 1029: </table> 1030: Fig. 2.3.6D � Dump of the resource properties hash. Excerpt of information 1032: gathered about links and link conditions between resources in subroutine 1033: loadmap. 1035: 1037: 1038: <table border=1 cellspacing=0 cellpadding=0> 1039: <tr> 1040: <td width=443 valign=top class="Normal"> 1041: 0 : true:normal 1042: 1 : user.assessments[this./msu/smith/racecar.problem].status=solved:force 1043: 2 : user.assessments[this./msu/smith/racecar.problem].answer=friction:stop 1044: 3 : user.assessments[this./msu/smith/racecar.problem].answer=sliding:stop 1045: 4 : user.assessments[this./msu/smith/racecar.problem].answer=nonconstant:stop 1046: 5 : user.assessments[this./msu/korte/tests/part11.problem].status=solved:stop 1047: 6 : user.assessments[this./msu/korte/tests/part12.problem].status=solved:stop 1048: 7 : user.assessments[this./msu/korte/tests/part13.problem].status=solved:stop 1049: 8 : user.assessments[this./msu/korte/tests/pretest.problem].status=solved:stop 1050: 9 : user.assessments[this./msu/korte/tests/midterm.sequence].percent>60:stop 1051: 10 : user.assessments[this./msu/korte/tests/midterm.sequence].percent<10:force 1052: 11 : user.assessments[this./msu/korte/tests/final.sequence].percent>60:stop 1053: � 1054: </td> 1055: </tr> 1056: </table> 1057: Fig. 2.3.7 � Excerpt of the dump of the condition array constructed 1059: in procedure loadmap 1060: (the final syntax of conditions has not yet been determined) 1061: <h3><a name="_Toc514920455"></a><a name="_Toc421867118">Paths and Path Conditions</a></h3> 1062: The next mayor step will be to determine all possible paths and conditions 1063: leading up to a resource for access control. 1064: readmap checks if the course 1065: has a start resource from its map_start entry in the resource properties 1066: (Step R2), and if does not, continue to store the two global binary data 1067: structures (Steps R5,R6) � in this 1068: special case, all resources which are part of any maps in the course are 1069: assumed to be accessible. 1070: If the course has a start resource, readmap calls the procedure traceroute (Fig. 2.3.8A) with the following parameters (Step R4): The cumulative condition along this path or route 1075: so far is set to �true� (the map is accessible); the resource ID of the 1076: start resource of the course map; and an empty list for all resources processed 1077: so far along this route. It is again important to note that all variables 1078: except the global binary structures are local to traceroute, 1079: since traceroute will recursively 1080: call itself whenever there is a branching to follow all possible paths of 1081: the maps. 1082: traceroute will establish 1083: a section within the resource properties hash that builds up all conditions 1084: leading up to a resource. Fig. 2.3.8B shows an excerpt of the final result. For example, resource 2.5, the 1086: introduction to part 1, can be reached under condition 8 (see Fig. 1087: 2.3.7), meaning, after solving the 1088: pretest problem. 1089: traceroute first checks 1090: if the resource has already been processed on this route by its resource 1091: ID (Fig. 2.3.8A, Step 1092: T1) � this test avoids that traceroute runs into endless loops when 1094: the links on the map loop. Next, the resource ID is added to the list of 1095: processed resources on this route (Step T2). 1096: The resource conditions are now OR�d with the cumulative conditions on 1097: this route (Step T3) � the route 1098: represents another way of getting to the resource. A small routine with 1099: simplification rules for boolean expressions is called to simplify the potentially 1100: very long expression. 1101: In the next step, it is determined if the resource is itself a map (Step 1102: T4). If it is, the exit route conditions 1103: can differ from the entry route condition by all additional conditions along 1104: the paths in the embedded maps (for non-map resources, entry and exit route 1105: conditions are the same). If however the embedded map does not have a start 1106: resource (Step T5), that 1107: is not the case � again, the missing of entry point to an embedded link 1108: structure is interpreted as the resources being openly accessible. 1109: If the embedded map does have a start resource, traceroute is called recursively with 1111: the current route conditions, the ID of the start resource of that map, 1112: and the list of already processed resource IDs (Step T6). Upon return, if the embedded map does not have a finish resource, the 1114: entry and exit conditions of this map are assumed to be the same (Step 1115: T7). If the map had a finish resource, 1116: the route condition so far is set to the resource condition of the finish 1117: resource of the embedded map (Step T8) 1118: � in order go on from here, the user would have had to reach the finish 1119: resource of the embedded map. 1120: Now the route conditions are correctly set for exiting the resource and 1121: going on from here. traceroute now 1122: loops over all outgoing links of the resource (Step T9). If the link does have a link condition (Step 1124: T10), then for this path, the cumulative 1125: route condition so far AND the link condition (Step T11). If there is no link condition, then there is no 1127: change in route conditions (Step T12). 1129: To further process the routes along this link, traceroute is called recursively with 1131: the resource ID of the destination resource of the link, the new route conditions, 1132: and the list of already processed resources (Step T13). traceroute 1134: returns after processing the last outgoing link of the resource it had been 1135: called for. 1136: Fig. 2.3.8B shows part of the output 1137: of traceroute for 1138: the example Fig. 2.3.4. 1139: 1141: <img border=0 width=432 1142: height=557 id="_x0000_i1035" src="handout_files/image011.jpg"> 1143: Fig. 2.3.8A � Flow chart of procedure traceroute 1146: 1148: <table border=1 cellspacing=0 cellpadding=0> 1149: <tr> 1150: <td width=443 valign=top class="Normal"> 1151: conditions_1.1: 0 1152: conditions_1.11: 1153: (((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)) 1154: conditions_1.15: 1155: ((((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)))&9 1156: conditions_1.2: 1157: (((((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)))&9)&11 1158: conditions_1.20: 0 1159: conditions_1.29: 1160: ((((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)))&9 1161: conditions_1.36: 1162: ((((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)))&10 1163: conditions_1.5: 0 1164: conditions_1.9: 8 1165: conditions_2.1: 8 1166: conditions_2.12: 8 1167: conditions_2.13: 8 1168: conditions_2.19: 8 1169: conditions_2.2: 1170: (((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)))|((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)) 1171: conditions_2.24: ((8&5)|(8&7)|(8&6)) 1172: conditions_2.5: 8 1173: conditions_2.6: 8 1174: conditions_3.1: ((8&5)|(8&7)|(8&6)) 1175: conditions_3.15: ((8&5&4)|(8&7&4)|(8&6&4)) 1176: conditions_3.2: ((8&5&2)|(8&5&3)|(8&5&4)|(8&5&1)|(8&7&2)|(8&7&3)|(8&7&4)|(8&7&1)|(8&6&2)|(8&6&3)|(8&6&4)|(8&6&1)) 1177: conditions_3.5: ((8&5)|(8&7)|(8&6)) 1178: conditions_3.6: ((8&5&2)|(8&7&2)|(8&6&2)) 1179: conditions_3.8: ((8&5&3)|(8&7&3)|(8&6&3)) 1180: </td> 1181: </tr> 1182: </table> 1183: Fig. 2.3.8B � Dump of resource properties hash. Excerpt of cumulative 1185: link conditions to reach a certain resource. 1186: <h3><a name="_Toc514840865"></a><a name="_Toc514920456"></a><a 1187: name="_Toc421867119">Multivalued Boolean Evaluation of Link Priorities</a></h3> 1188: When a user accessed a resource on a map and desires to access the �next� 1189: resource, the request is processed by a number of steps. From the data examplified 1190: in Fig. 2.3.6C, it is determined 1191: which outgoing links exist. From the data in Fig. 2.3.6D 1192: it is determined to which resources those links lead. For each of the resources, 1193: the expressions in Fig. 2.3.8A 1194: are evaluated as follows. Stored in the session environment is the evaluation 1195: of the table Fig. 10, where the boolean part is evaluated as �0� or �1�. 1197: In addition, a multivalued boolean value is computed incorporating the condition 1198: priority. A false blocking condition is assigned the value zero, all other 1199: false conditions the value 1. A true forced condition is assigned the value 1200: 3, all other true conditions the value 2. 1201: In the expressions Fig. 2.3.8A an �&� (�AND�) is processed as the minimum (min) operation, a �|� 1203: (�OR�) is processed as the maximum (max) operation. The outcome �0� means 1204: �blocked�, the outcome �1� mean �not recommended�, the outcome �2� recommended, 1205: and the outcome �3� forced. 1206: </div> 1207:   1208: </div> 1209: 1211: <div class=Section2> </div> 1212: </body> 1213: </html>