Abstract:
The method and system of this invention analyzes a document to generate margin or end notes of references to portions of other documents and other portions of the same documents that relate to annotated passages in the document or to the entire document. The method and system of the invention is responsive to the annotation of a passage of a document to generate a query that retrieves portions of documents that have similar content to the annotated passage. The retrieved portions are made available to the reader through selectable links placed in the margin near the annotated passage in a display of the document. Additionally, the method and system of the invention provides end notes with links to portions that are similar in content to the overall content of the annotated document. The method and system of the invention assists the reader by passively generating selectable links to related portions to assist the user in relating the new document to other portions of documents.

Description:
This is a Continuation-in-Part of application Ser. No. 08/929,426 filed on Sep. 15, 1997. The entire disclosure of the prior application(s) is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates generally to electronic document reading systems. In particular, this invention is directed to an electronic document reading system that suggests other related documents when displaying a first document. 
     2. Description of Related Art 
     Retrieving documents similar to a document identified by the user as being related is known as relevance feedback. Relevance feedback is described in “Introduction to Modem Information Retrieval”, G. Salton et al., McGraw Hill, (1983), incorporated herein by reference in its entirety. Interfaces that support relevance feedback conventionally require explicit action on the part of the reader and do not spontaneously offer suggestions of relevant documents. Information exploration interfaces designed for window-based computing environments typically present search results for other relevant documents via lists in a separate window or by replacing the visible document with the search results. These systems are very intrusive and interrupt the reading process. 
     Hypertext interfaces display links to documents relevant to a source document either by providing a margin that contains the links or by embedding the links in the text of the source document in the manner pioneered by “Hyperties.” This system is described in “User Interface Design for the Hyperties Electronic Encyclopedia”, by Shneiderman,  Proceedings of Hypertext  &#39;87, November 1987, Chapel Hill, N.C. incorporated herein by reference in its entirety. However, these links are static and are created along with the source document by the hypertext author. Some systems, such as Trellis, display links dynamically, but only from a fixed set of previously-defined links. Trellis is described in “Programmable Browsing Semantics and Trellis”, by R. Furuta et al.  Proceedings of Hypertext  &#39;89, November 1989, Pittsburgh, Pa., ACM Press, incorporated herein by reference n its entirety. 
     The HieNet System uses inter-node similarity measures to create hypertext links based on links previously created by the hypertext author. This system is described in “Hienet: A User-Centered Approach for Automatic Link Generation”, D. T. Chang,  Proceedings of Hypertext  &#39;93, November 1993, Seattle, Wash., ACM Press, incorporated herein by reference in its entirety. When the author creates a link from a document A to a document B, the system automatically adds links from all documents similar to document A to all documents similar to document B. Anchors for these automatically-generated links are represented by icons in the margin of the various documents. Clicking on an icon displays a pop-up menu that contains a list of possible destination documents that are ranked by relevance to the query. Again, this system relies on links previously created by the author. 
     Other conventional systems relate to hypertext-like ways of displaying search results. HieNet displays automatic links in the margin, but anchors in the margin are not relevant to the content of the passage adjacent to the anchor. HieNet does not distinguish between document-document and passage-document links. Furthermore, HieNet does not indicate the number and nature of the documents reachable through the margin links. 
     Visualization of Information Retrieval System (hereinafter VOIR) is described in “Queries? Links? Is There a Difference?”,  Proceedings of CHI  &#39;97, G. Golovinsky, March 1997, Atlanta, Ga., ACM Press and in “What the Query Told the Link: The Integration of Hypertext and Information Retrieval”,  Proceedings of Hypertext  &#39;97, G. Golovinsky, April 1997, Southhampton, UK, ACM Press, each incorporated herein by reference in its entirety. VOIR is a mechanism that dynamically creates and resolves hypertext links with queries that are computed from the text surrounding a selected anchor. VOIR uses queries to retrieve sets of documents that are related to the passage containing the selected anchor. VOIR does not show the user links that have pre-established relationships. Rather, to submit a query and to establish a relationship, the user has to pause and select an anchor. VOIR was designed specifically to support interactive information exploration, rather than to facilitate the reading process. Thus, VOIR&#39;s focus is supporting navigation between documents. The user is thus expected to devote much cognitive effort to browsing. Furthermore, VOIR does not permit the user to annotate or tag documents. VOIR also does not indicate which link was selected to generate a particular display. 
     A background information retrieval process called the Remembrance Agent (hereinafter RA) is described in “A Continuously Running Automated Information Retrieval System”, B. J. Rhodes et al.  Proceedings of The First International Conference on the Practical Application of Intelligent Agents in Multi-Agent Technology , PAAM &#39;96, April, 1997reference in its entirety. RA operates in an EMACS text window and suggests documents related to the last few lines of text typed by the user. RA is designed to search through a user&#39;s private data to suggest documents related to the text being typed. However, these suggestions are ephemeral and relate only to text that is currently being written. RA does not support reading tasks because it continuously replaces suggestions as the user edits the document. 
     QRL is a query-based information exploration interface that uses ink-like marks on text to specify boolean queries. This system is described in “Queries-R-Links: Graphical Markup for Text Navigation”, by G. Golovchinsky et al.,  Proceedings of INTERCHI  &#39;93, April 1993, Amsterdam, The Netherlands, ACM Press, incorporated herein by reference in its entirety. Query terms are selected with rectangles. Lines connect the rectangles to represent boolean AND operators. 
     All of these systems require extensive user interaction to generate links to related documents or only support writing. An electronic document reading system is needed that passively and unobtrusively generates links to related documents to support reading. 
     SUMMARY OF THE INVENTION 
     This invention provides a method and a system for passively showing the reader related documents without interfering with the reading process. 
     The invention further provides intuitive support for reading by automatically detecting portions of other documents or other portions of the same document that are potentially of interest to the reader based on the reader&#39;s interaction with the portion of the source document being read. When people read text, they often make annotations to highlight interesting or controversial passages and terms. The presence or relative density of such marks and scribbles may be used as an indicator of the relative interest that the reader has in a particular passage. When a large body of documents related to the document being read is available, the reader may be interested in finding related portions of other documents or other portions of the same document as part of the reading process. 
     References to portions of other documents or to other portions of the same document that are related to specific passages of interest to the user are placed in the source document&#39;s margins and references to other documents that are similar overall to the source document are inserted as end notes. The system and method of this invention maintain the links once they have been identified to facilitate non-linear reading and skimming. 
     The system and method of this invention infer a user&#39;s interests from annotations that are made to a source document by the user while the user is reading the source document. Therefore, the system and method of this invention minimize cognitive overhead in at least two ways: 1) no explicit query is required to identify portions of other documents and other portions of the same document that are related to the portion of the source document that has been annotated by the user; and 2) selectable links to the portions of other related documents or other portions of the same document are provided unobtrusively in the margins and at the end of the source document. An example of this is shown in FIGS. 2 and 3, respectively. 
     The system and method of this invention also introduce suggestions to the reader in a manner that is compatible with other interactions, rather than burdening the user with modal dialogues. Portions of other documents or other portions of the same document that are suggested by the method and system of this invention are accessible by following selectable links. However, the system and method of this invention does not force the user to act on a suggestion when it is made. Rather, the user can act on the suggestion when (or if) it makes sense to the user to do so. The system and method of this invention represent the type of the suggested or referenced portion with an icon and provide a textual label to the icon to give users a better understanding of the target of the link. 
     These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments of this invention will be described in detail, with reference to the following figures, wherein: 
     FIG. 1 is a block diagram of one embodiment of the electronic document reading system of this invention; 
     FIG. 2 shows a source document having an icon in the margin adjacent to an annotated passage; 
     FIG. 3 shows another source document having an endnote; and 
     FIGS. 4A and 4B show a flowchart outlining a control routine for one embodiment of this invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a block diagram of one embodiment of a document reading system  10  according to this invention. The document reading system  10  includes a processor  12  communicating with a first memory  14  that stores a source document  16  that is currently being read by a user on a display  18 . The processor  12  also communicates with a second memory  20  that stores potentially related target portions  22 . The target portions may, optionally, include portions of the source document  16 . The target portions  22  may include whole or entire documents. 
     A user interacts and controls the document reading system  10  through any number of conventional input/output devices  24 , such as a mouse  26 , a keyboard  28 , or a pen-based interface  30 . The input/output devices  24  communicate with an input/output interface  31  that, in turn, communicates with the processor  12 . 
     As shown in FIG. 1, the system  10  is preferably implemented on a programmed general purpose computer. However, the system  10  can also be implemented using a special purpose computer, a programmed microprocessor or microcontroller and any necessary peripheral integrated circuit elements, an ASIC or other integrated circuit, a hardwired electronic or logic circuit such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. In general, any device on which a finite state machine capable of implementing the flowchart shown in FIGS. 4A and 4B can be used to implement the system  10 . 
     Additionally, as shown in FIG. 1, the storage devices or memories  14  and  20  are preferably implemented using static or dynamic RAM. However, the devices  14  and  20  can also be implemented using a floppy disk and disk drive, a writable optical disk and disk drive, a hard drive, flash memory or the like. Also, it should be appreciated that the devices  14  and  20  can be either distinct portions of a single memory or physically distinct memories. 
     Further, it should be appreciated that the links  15  and  17  connecting the devices  14  and  20  and the processor  12  can be a wired or wireless link to a network (not shown). The network can be a local area network, a wide area network, an intranet, the Internet or any other distributed processing and storage network. In this case, the electronic document  16  is pulled from the physically remote memory device  14  through link  15  for processing in the processor  12  and the target portions  22  are remotely accessed through the link  17  according to the method outlined below. In this case, the electronic document  16  and the target portions  22  can also be stored locally in a portion of some other memory device of the system  10  (not shown). 
     The method of this invention identifies two kinds of target portions related to a passage of each source document  16 . The two types are: 1) target portions  22  that are related to specific annotated passages of the source document; and 2) target portions  22  that are related to the overall source document. Once a relationship is established between a passage of the source document and the target portions  22 , the target portions  22  may be displayed by clicking on selectable links in the display of the source document  16 . The system and method of this invention may optionally show in a single display all target portions  22  that have been identified as being related to one or more passages in the source document  16 . 
     Examples of references to the two types of target portions  22  are shown in FIGS. 2 and 3. A target portion  22  related to a specific passage  32  in the source document  16  is identified by a margin representation  34  placed in the margin of the source document  16  near the related passage  32 . As shown in FIG. 3, a target portion  22  that is related to the source document  16  as a whole is annotated and shown as an end-note  36  to the source document. The end note  36  may include the type, the title and the summary information of the document from which the target portion originated. 
     This invention is not to be limited by the type of annotation or the method or system that determines the context of an annotation. Annotations may be structured or unstructured. 
     FIGS. 4A and 4B show a flowchart outlining the control routine for one embodiment of the method of this invention. The control routine starts at step S 100  and continues to step S 110 . In step S 110 , the control routine receives a source document  16  as input and continues to step S 120 . In step S 120 , the control routine segments the source document into a series of passages and the control routine continues to step S 130 . The segmentation in step S 120  may be performed by any conventional segmentation system or method. In step S 130 , the control routine stores the segments of the source document as additional target portions  22  and continues to step S 140 . In this manner, the segmented passages of the source document are made available as potential related portions to be referenced. 
     In step S 140 , the control routine determines whether an annotation has been input into the system. The annotation may be input in any number of different ways using any number of different systems. One preferred method of inputing an annotation is by marking directly on a display of the source document using a stylus in a pen-based input device. In step S 140 , if the control routine determines that an annotation has not been input into the system, the control routine returns to step S 140 . If the control routine determines in step S 140  that an annotation has been input then the control routine continues to step S 150 . 
     In step S 150 , the control routine determines the context for the annotation. The context may be determined in step S 150  by any conventional system and method. Preferably, the context of an annotation is determined using bounding boxes. The system generates a bounding box around the annotation mark and expands the bounds of the box to define the context. The horizontal bounds are extended horizontally to the edge of the text and the vertical bounds are extended vertically to include complete words, sentences or paragraphs. The amount of text bounded by the bounding box is initially established using predetermined preferences which way be adjusted to suit the user. Additionally, the user may directly manipulate the bounding box to determine the context of an annotation. After the control routine determines the context of the annotation in step S 150 , the control routine continues to step S 160 . 
     In step S 160 , the control routine analyzes the context of the annotation and generates a query that will be used to search the database of target portions  22 . The system and method of this invention derives the query from the text of the annotated passage and from the nature of the annotation. The control routine then continues to step S 170  where the query is used to identify related target portions  22 . The related target portions  22  are identified using the query generated in step S 160  by determining the best-matching target portion and which exceeds a predetermined threshold. Any number of conventional methods or systems may be used to determine the best matching target portion and it is to be understood that this invention is not limited to any particular searching method or system. Additionally, the predetermined threshold may be adjusted by the user in accordance with the user&#39;s preferences. 
     The control routine then continues to step S 180  where links to each of the identified target portions are displayed. If the link corresponds to a target portion that is related to the context of a particular annotation then the link is displayed in a margin adjacent to the annotation as a margin representation  34  as shown in FIG.  2 . Alternatively, if the control routine identifies a target portion in step S 170  that is related to the source document as a whole then the control routine displays a link to the target portion as an end note  36  as shown in FIG.  3 . The control routine then continues to step S 190 . 
     In step S 190 , the control routine determines if a user has selected a link that has been displayed. If in step S 190 , the control routine determines that a link has been selected, then the control routine continues to step S 200 . In step S 200 , the control routine displays the target portion that corresponds to the selected link. The control routine then continues to step S 210  where the control routine stops. 
     In an alternative embodiment, which is not shown, the control routine may process the displayed target portion as the input source document and return to step S 110  where the target portion is processed. In another embodiment, if, in step S 190 , the link is selected then the entire document from which the identified target portion related to the selected link is displayed and the entire document from which the target portion originated may be input as a source document in step S 110 . However, if in step S 190 , a link is not selected then the control routine continues to step S 220 . 
     In step S 220 , the control routine determines if the user has input an end routine command. If in step S 220  the user has not input a end routine command the control routine returns to step S 140 . Alternatively, if in step S 220 , the control routine determines that the user has input an end routine command, the control routine continues to step S 210  where the control routine stops. 
     The control routine of the method and system of this invention may be set to operate when the document reading system  10  is turned on or upon the receipt of a user input command (such as an annotation). 
     Additionally, the number of target portions that are identified and/or displayed may be adjustable using a predetermined threshold. This threshold can prevent the display of too many links that may obscure or prevent the system from being useful. For example, the system may identify a plurality of target portions based upon their relatedness to the source document, clusters the identified plurality of target portions and selects at least one of the plurality of identified target portions for each cluster that typifies all of the identified target portions within each respective cluster, wherein the selectable link references the selected at least one of the plurality of second portions. 
     Target portions may be identified using any one or more of conventional methods. For example, the relatedness of a target portion may be determined using a text-based statistical similarity method or may use a full-text boolean or probabilistic method. Other examples include linguistic or logical analysis methods, speaker identification or recognition and image similarity algorithms. The invention is not limited to any now known or future method or system for determining the relatedness of the target portions to the source document. 
     The method and system of this invention use a passage or portion of a document rather than the entire document as the unit of retrieval. The target portions  22  are indexed by segmenting documents into tiles that contain spans of statistically similar text. The tiles are used as the unit of retrieval rather than documents because long documents that address many topics tend to match queries poorly, whereas specific portions of those documents may match quite well. 
     The method and system of this invention recognize several distinct ink patterns from which queries are computed. The ink patterns or marks include underlined words, circled words, circled passages and marginal annotations. Preferably, each type of annotation results in a different query for the search engine. For example, marks that select specific words translate into queries that emphasize those words over others in the same sentence and marks that select longer passages generate queries that search for similar phrases. Alternatively, a separate query may be computed for each stroke. 
     Ink strokes may also be grouped by time and type of annotation. For instance, annotation types may be distinguished by color and annotations having an identical or similar color may be grouped to generate a query. 
     It is to be understood that the term annotation as used herein is intended to include text, digital ink, audio, video or any other input associated with a document. It is also to be understood that the term document is intended to include text, video, audio and any other media and any combination of media. Further, it is to be understood that the term text is intended to include text, digital ink in stroke or bitmap format, audio, images, video or any other structure or content of a document. It is also intended to be understood that the term “annotation” is intended to include text, digital ink, audio, images, video or any other input associated with a document. 
     It is to be understood that the term “similarity” or “relatedness” is intended to include any measure of a document or portion of a document&#39;s relatedness or relevance to a portion of another document or portion of a document to include other portions of the same document. 
     While this invention has been described with the specific embodiments outlined above, many alternatives, modifications and variations are and will be apparent to those skilled in the art. Accordingly, the preferred embodiments described above are illustrative and not limiting. Various changes may be made without departing from the spirit and scope of the invention.