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

Description:
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 Modern 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 in 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, 1997, London, UK, incorporated herein by reference 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 specie 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 documents potentially of interest to the reader based on the reader&#39;s interaction with 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 documents as part of the reading process. 
     References to documents related to specific passages of interest to the user are placed in the source document&#39;s margins and references to documents 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. 
     A user&#39;s interests are inferred from annotations made while reading the source document. Therefore, the system and method of this invention minimize cognitive overhead in two ways: 1) no expressive query is required to identify documents related to the source document; and 2) selectable links to the related documents are provided unobtrusively in the margins and at the end of the document, this is shown in FIGS. 2 and 3, respectively. 
     The system also introduces suggestions to the reader in a manner compatible with other interactions, rather than burdening the user with modal dialogues. Suggested documents are accessible by following the selectable links. However, the user does not have to act on a suggestion when it is made. Rather, the user can act on the suggestion when (or if) it makes sense to do so. The system and method of this invention represent the type of the referenced document with an icon and provide a textural 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 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 
     FIG. 4 is 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 documents  22 . 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 FIG. 4 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 and physically remote memory device  14  through link  15  for processing in the processor  12  according to the method outlined below. In this case, the electronic document  16  can be stored locally in portion of some other memory device of the system  10  (not shown). 
     The method of this invention identifies two kinds of target documents  22  for each source document  16 . The two types of target documents are: 1) target documents that are specifically related to annotated passages; and 2) target documents that are generally related to the overall source document. Once a relationship is established between the source document and the target documents  22 , the target documents may be displayed by clicking on selectable links in the displayed document  16 . 
     References to the two types of target documents  22  is shown in FIG. 2. A target document  22  related to the 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 document  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  includes the type, the title and summary information. 
     FIG. 4 is a flowchart outlining a control routine for one embodiment of the method of this invention. Beginning in step S 100 , the control routine continues to step S 105  In step S 105 , the control routine determines if the user has made any annotations. If not, control loops back to step S 105 . If so control continues to step S 110 . In step S 110 , the control routine determines the annotation of the source document mode by the user. Next, in step S 120 , the control routine analyzes the text of the source document and the annotation to determine the passage being annotated. A passage may include a paragraph marked with a margin bar, an underlying sentence or phrase, or the context of one or more circled terms. Then in step S 130 , the control routine generates a query from the passage. The query includes content-bearing terms from the identified passage that are weighted to give importance to any circled words. Next, in step S 140  the control routine searches the target document using the query to identify documents that are related to the passage. Then, at step S 150 , the search results are clustered. Clustering is preferably performed in a manner similar to that described in “Reexamining the Cluster Hypothesis: Scatter/Gather on Retrieval Results”, M. A. Hearst et al.,  Proceedings of ACM SIGIR  &#39;96, August 1996, Zurich, Switzerland, incorporated herein by reference in its entirety. 
     Next, in step S 160 , the control routine selects a typical document from each cluster. These documents are further filtered by a user-specified similarity threshold in step S 170 . Then, in step S 180 , the remaining documents are identified by displaying links to those documents in the margin of the source document adjacent to the passage from which the query was generated. Each selectable link may be an icon representing a type of the selected and filtered target document and a short title. 
     Next, in step S 190 , the control routine determines if a user has selected a selectable link in the current source document. If in step S 190 , a user has selected a selectable link, the control routine proceeds to step S 200 . In step S 200 , the target document is displayed as the new current source document, control then continues back to step S 105 , where it waits for another annotation to be made. Alternatively, if in step S 190 , no selectable link is selected, then the control jumps directly back to step S 105 . The control routine continues until the user has closed all open source documents  16  displayed on the display  18 . 
     To compute end notes the flowchart of FIG. 4 can be used with slight modifications. The control routine proceeds identically as described for the creation of margin notes from step S 100  through step S 120 . However, at step S 130  a weighted sum query is generated. In step S 130  terms that are explicitly identified by the reader and terms identified by standard relevance feedback techniques are used to construct weighted-sum queries at step S 130 . The identified terms are assigned weights based upon the annotations made to the document. For instance, words that have been expressly selected by the user are weighted the highest and words that occur in selected paragraphs are weighted higher than the remaining terms of the source document. 
     Documents that have been identified as related to the document using the weighted sum query generated in step S 130  are processed in a manner similar to the remaining steps S 140  through S 200  with the exception that the link is displayed as an end note in step S 180  rather than as a margin note. 
     It should be understood that either or both of these control routines may be running in the background of a document reading system of the invention. 
     Optionally, the system and method of this invention may derive summaries from documents through an automatic text summarization process in a manner similar to that described in “A Trainable Document Summarizer”, J. Kupiec et al.,  Proceedings of SIGIR  &#39;95, July 1995, Pittsburgh, Pa., ACM Press, incorporated herein by reference in its entirety. The summaries are then displayed as end notes. 
     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, audio, video or any other content of a document to include the document&#39;s structure. 
     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 as defined in the following claims.