1、student-adaptive educational systemshaiying dengics ucipapers for today methods and techniques of adaptive hypermedia (brusilovsky, p) metadoc: an adaptive hypertext reading system (boyle, c. and encarnacion) using bayesian networks to manage uncertainty in student modeling (conati, c. et al )method

2、s and techniques of ahpeter brusilovsky hcii, school of cs carnegie mellon universityoutline overviews of ah methods and techniques of content adaptation methods and techniques of adaptive navigation supportdefinition of ah all hypertext and hypermedia systems which reflect some features of the user

3、 in the user model and apply this model to adapt various visible aspects of the system to the user. adaptation techniques refers to methods of providing adaptation in existing ah systems. adaptation methods are defined as generalizations of existing adaptation techniques.adapting to what knowledge:

4、overlay model or stereotype model users goal: similar to the overlay model hierarchy (a tree) of tasks background and experience preferencemethods of content adaptation additional explanations prerequisite explanations comparative explanations explanation variants sorting (the fragments of info by t

5、he relevance)techniques of content adaptation(1) lower level: conditional text all possible info is divided into several chunks of texts, which is associated with a condition on the level of the user the info chunk presented only when the condition is true item/ip, lisp-critic, c-booktechniques of c

6、ontent adaptation(2) higher level: stretchtext replace the activated hotword extending the text of the current page. collapse the non-relevant stretchtext extension, uncollapse the relevant ones. collapsed and uncollapsed hotwords can be transferred with each other kn-ahstechniques of content adapta

7、tion(3) page variants techniques: two or more variants of the same page with different presentations of the same content for different user according to the user stereotype orimuhs, wing-mit, anatom-tutor, c-book. fragment variants: variants of explanations for each concept - anatom-tutor combinatio

8、n of the two above: anatom-tutortechniques of content adaptation(4) frame-based technique: info about a concept in form of a frame, frames forms a slot, slots forms a scheme. slots or schema chosen by some rules. hypadapter and epiaim push: a combination of stretchtext and frame-based technique, whi

9、ch has its own entity type of info, similar to frame-based model and a interface similar to metadoc stretchtext interface.methods of adaptive navigation support(1) global guidance: give suggestion at each step of browsing about the next link: webwatcher adaptively sort all the links from the given n

10、ode according to the global goal: adaptive hyperman and hyperflexmethods of adaptive navigation support(2) local guidance: similar to the global guidance, but different in terms of the local goal, based on the preferences, knowledge and background methods of adaptive navigation support(3)local orien

11、tation support: to help the user in local orientation- providing additional info about the current node- limiting the navigation opportunities and let user concentrate on the most relevant linksmethods of adaptive navigation support(4) global orientation support help understand the overall structure

12、 of the hyperspace and the users absolute position. instead of visual landmarks and global maps directly, provide more support by applying hiding and annotation technology. providing different annotation based on the knowledge level.methods of adaptive navigation support(5) managing personalized vie

13、ws: protect users from the complexity of the overall hyperspace by organizing personalized goal-oriented views, each of which is a list of links to all relevant hyper documents basartechniques of adaptive navigation support(1) hyperflex: provides with global and local guidance by displaying an order

14、ed list of related nodes. adaptive hyperman: inputs including user background, search goal interest of current node, etc, outputs an ordered set of relevant doc. hypadapter: use a set of rules to calculate the relevance of links for each slot.techniques of adaptive navigation support(2) hypertutor a

15、nd sypros: use rules to decide the visible concepts and nodes based on the concept types, the types of links to other concepts and the current state of users knowledge. hynecosum: supports both goal-based and experience-based methods of hiding using hierarchies of tasks.techniques of adaptive naviga

16、tion support(3) isis-tutor, item/pg and elm-art: support several methods of local and global orientation support based on annotation and hiding, links to the concepts with different educational states are annotated differently using different colors. hypercase: only known example of map adaptation:

17、supports local and global orientation by adapting the local and global mapssummary identified seven adaptation technologies for ah: adaptive text presentation adaptive multimedia presentation direct guidance adaptive sorting hiding annotation of links map adaptation metadoc: an adaptive hypertext re

18、ading system craig boyle antonio o encarnacion overview simple online text documentation: fixed organization.hypertext: present through link selectionadaptive hypertext: actively participate the reading.adaptivity extends the conventional flexibility of the hypertext from the network level to the no

19、de level. metadoc: stretchtextexample: stretchtextuser model adapts to the reader, instead of a document contains a representation of the readers knowledge. participates in the reading process.related work “stretchtext”: (nelson, 1971)change the depth of the information in a node. stretching: replac

20、e the whole node , similar to goto links replacement-buttons dynatext: limited form of stretchtext.metadoc to other doc forms user modeling: active document stretchtext: three dimensional reading and writing hypertext: non-sequential reading and writing online documentation: hierarchical retrieval p

21、rinted text: linear reading and writing interactive agent store the knowledge about the reader used to vary the level of detail in the doc. user level and levels of information users and stereotype: novices, beginners, intermediates or experts based on the knowledge of unix/aix and general computer

22、concepts. concept levels: the same as above. metadoc varies the amount of explanation or detail info to present the correct level of info based on the internal stereotype info of a concept and the readers knowledge level.metadoc document choose different versions of a single node manually or automat

23、ically selectively adjust parts of the node instead of adjusting the whole nodewriting stretchtext smooth transition familiar landmarks for different levels common node identifiers be orderedstretchtext in metadoc vary the info in terms of either explanation or amount of detail choose the embedded a

24、nd appended stretchtext: less confusing selected by mouse operations which is context-sensitive and recursivedefault presenting rules explanation of concepts associated with higher levels are automatically provided for lower level users. explanation of concepts associated with lower levels unnecessa

25、ry for higher level users are suppressed. higher level details not necessary for understanding a concept are suppressed for lower level users details of equal or lower level concepts are automatically displayed for higher level users.architecture of metadoc(1) 3d document component: determines the f

26、inal form of the node presented to the user and receives commands from the user, composed of the document presentation manager and the base documentarchitecture of metadoc(2) intelligent agent: dynamically keeps track of the user knowledge level, automatically matching the presented info depth to th

27、e user level, composed of a user model and the inference engine domain concepts: bridge the gap between the above twouser modeling explicit modeling: give user the option of explicitly changing the user model within the session implicit modeling: stretchtext operation: request for more or less expla

28、nation command for less or more detailevaluation metadoc evaluated with respect of comprehension and location of specific info. compared three systems: metadoc, hypertext-only and stretchtext versions.metadoc evaluationhypertextstretchtextmetadocexpertnovice expert novice expert novicereading comp.

29、time (sec.)17801930125017808101420reading comp. correct536.5777mean search time (sec.)755725645530555575significant results of metadoc evaluationdiscussion of results users of ah doc spent less time answering the comprehension questions correctly users of adaptive documents spent less time answering

30、 search and navigation questions metadoc had greater impact on novice users than experts.conclusion metadoc provides an environment in which the user read a hypertext document that will adapt to his/her needs. can help improve readers performance.using bayesian networks to manage uncertaintyin stude

31、nt modeling cristina conati abigail gertner and kurt vanlehnandes systems main contribution provides a comprehensive solution to the assignment of credit problem for both knowledge tracing and plan recognition supports prediction of student actions during problem solving,problem solving interface pr

32、ovides two kinds of help: error help procedural helpexample studying interface under se-coach which gets the students to self-explain examples step correctness: by rule browser step utility: by plan browserandes approach to student modelingissues in real world(1) 1. context specificity 2. guessing 3

33、. mutually exclusive strategies 4. old evidence 5. errorsissues in real world(2) 6. hints 7. reading latency 8. self-explaining ahead 9. self-explanation menu selectionsnetworks of andes data structure: solution graph knowledge-based model construction approach for problem solving: all the correct s

34、olution for example studying: one single solutionencodings givens: (scalar (kind mass)(bod y block-a)(magni tude 50)(units kg) problem goal: (goal-problem (is find-normal-force)(applied-to block-a)(app lied-by table)(time 1 2) sub-goalsstructure of the networks(1) the domain-general part: represents

35、 student long-term knowledgestructure of the networks(2) task-specific part: modeling for problem solving errors of omission and errors of commission updating the student model after a hint using the network to generate helpmodeling for example studying(1) p(ra= t | all parents = t) =1 - a address the issue of self-explaining ahead represents a students tendency to self-explain an inference as soon as she has the knowledge to do somodeling for example studying(2) the