Charles-Antoine Julien

Constructing a true LCSH tree of a science and engineering collection

The Library of Congress Subject Headings (LCSH) is a subject structure used to index large library collections throughout the world. Browsing a collection through LCSH is difficult using current online tools in part because users cannot explore the structure using their existing experience navigating file hierarchies on their hard drives. This is due to inconsistencies in the LCSH structure, which does not adhere to the specific rules defining tree structures. This article proposes a method to adapt the LCSH structure to reflect a real-world collection from the domain of science and engineering. This structure is transformed into a valid tree structure using an automatic process. The analysis of the resulting LCSH tree shows a large and complex structure. The analysis of the distribution of information within the LCSH tree reveals a power law distribution where the vast majority of subjects contain few information items and a few subjects contain the vast majority of the collection.

Reducing Subject Tree Browsing Complexity

Many large digital collections are currently organized by subject; although useful, these information organization structures are large and complex and thus difficult to browse. Current online tools and visualization prototypes show small, localized subsets and do not provide the ability to explore the predominant patterns of the overall subject structure. This study describes subject tree modifications that facilitate browsing for documents by capitalizing on the highly uneven distribution of real-world collections. The approach is demonstrated on two large collections organized by the Library of Congress Subject Headings (LCSH) and Medical Subject Headings (MeSH). Results show that the LCSH subject tree can be reduced to 49% of its initial complexity while maintaining access to 83% of the collection, and the MeSH tree can be reduced to 45% of its initial complexity while maintaining access to 97% of the collection. A simple solution to negate the loss of access is discussed. The visual impact is demonstrated by using traditional outline views and a slider control allowing searchers to change the subject structure dynamically according to their needs. This study has implications for the development of information organization theory and human–information interaction techniques for subject trees.

Exploiting major trends in subject hierarchies for large-scale collection visualization

Many large digital collections are currently organized by subject; however, these useful information organization structures are large and complex, making them difficult to browse. Current online tools and visualization prototypes show small localized subsets and do not provide the ability to explore the predominant patterns of the overall subject structure. This research addresses this issue by simplifying the subject structure using two techniques based on the highly uneven distribution of real-world collections: level compression and child pruning. The approach is demonstrated using a sample of 130K records organized by the Library of Congress Subject Headings (LCSH). Promising results show that the subject hierarchy can be reduced down to 42% of its initial size, while maintaining access to 81% of the collection. The visual impact is demonstrated using a traditional outline view allowing searchers to dynamically change the amount of complexity that they feel necessary for the tasks at hand.

Capitalizing on Information Organization and Information Visualization for a New-Generation Catalogue

Subject searching is difficult with traditional text-based online public access library catalogues (OPACs), and the next-generation discovery layers are keyword searching and result filtering tools that offer little support for subject browsing. Next-generation OPACs ignore the rich network of relations offered by controlled subject vocabulary, which can facilitate subject browsing. A new generation of OPACs could leverage existing information-organization investments and offer online searchers a novel browsing and searching environment. This is a case study of the design and development of a virtual reality subject browsing and information retrieval tool. The functional prototype shows that the Library of Congress subject headings (LCSH) can be shaped into a useful and usable tree structure serving as a visual metaphor that contains a real world collection from the domain of science and engineering. Formative tests show that users can effectively browse the LCSH tree and carve it up based on their keyword search queries. This study uses a complex information-organization structure as a defining characteristic of an OPAC that goes beyond the standard keyword search model, toward the cutting edge of online search tools.

Cardinal: novel software for studying file management behavior

In this paper we describe the design and trial use of Cardinal, novel software that overcomes the limitations of existing research tools used in personal information management (PIM) studies focusing on file management (FM) behavior. Cardinal facilitates large‐scale collection of FM behavior data along an extensive list of file system properties and additional relevant dimensions (e.g., demographic, software and hardware, etc). It enables anonymous, remote, and asynchronous participation across the 3 major operating systems, uses a simple interface, and provides value to participants by presenting a summary of their file and folder collections. In a 15‐day trial implementation, Cardinal examined over 2.3 million files across 46 unsupervised participants. To test its adaptability we extended it to also collect psychological questionnaire responses and technological data from each participant. Participation sessions took an average of just over 10 minutes to complete, and participants reported positive impressions of their interactions. Following the pilot, we revised Cardinal to further decrease participation time and improve the user interface. Our tests suggest that Cardinal is a viable tool for FM research, and so we have made its source freely available to the PIM community.

Exact versus estimated pruning of subject hierarchies

Many large digital collections are organized by subject; these useful information organization structures are large and complex, thus difficult to browse. Current online tools and visualization prototypes show small localized subsets and do not provide the ability to explore the predominant patterns of the overall subject structure. This study builds on existing work concerning automatic subject hierarchy modification techniques that aim to facilitate browsing for documents by capitalizing on the highly uneven distribution of real-world collections. Specifically, previous work used an estimation of the number of accessible documents offered by each subject term, while the current study uses the exact number of accessible documents. The impact is demonstrated on a large collection organized using Medical Subject Headings (MeSH). Results show that, although computationally more demanding, pruning the MeSH hierarchy based on the exact access produces a different subject hierarchy under some conditions. The visual impact is demonstrated using traditional outline views. This study has implications for the development of information organization theory and human-information interaction techniques for subject hierarchies.

Improving Exploration of Topic Hierarchies: Comparative Testing of Simplified Library of Congress Subject Heading Structures

Many large digital collections are organized by sorting their items into topics and arranging these topics hierarchically, such as those displayed in a tree view. The resulting information organization structures mitigate some of the challenges of searching digital information realms; however, the topic hierarchies are often large and complex, and thus difficult to navigate. Automated techniques have been shown to produce significantly smaller, simplified versions of existing topic hierarchies while preserving access to the majority of the collection, but these simplified topic hierarchies have never been tested with human participants, and so it is not clear what effect simplification would have on the exploration and use of such structures for browsing and retrieval. This study partly addresses this gap by performing a comparative test with three groups of university students (N=62) performing ten topic hierarchy exploration tasks using one of three versions of the Library of Congress Subject Headings (LCSH) hierarchy: 1) the original LCSH hierarchy, acting as a baseline, 2) a shallower version of 1), and 3) a narrower version of 2). A quantitative analysis of measures of accuracy, time, and browsing shows that participants using the simplified trees were significantly more accurate and faster than those using the unmodified tree, and the narrower, balanced tree was also faster than the shallower tree. These results show that automated topic hierarchy simplification can facilitate the use of such hierarchies, which has implications for the development of information organization theory and human-information interaction techniques for similar information structures.

Mapping science using Library of Congress Subject Headings

Maps of scientific knowledge are generally created by analyzing scientific literature including journal articles, conference proceedings, books, and monographs. Although citation analysis is the most popular method for generating maps of science from scientific journal articles and their citations, other relationships between scientific topics can be used to map science. This study offers a map of science generated from examining non-fiction book topics and their relationships as defined by Library of Congress Subject Heading (LCSH) co-assignments. The resulting map reveals which sub-disciplines of science must be learned together, showing that Physics and Mathematics are the central topics required to practice science, which is not revealed by previous studies. This novel LCSH-based science map reveals new relations between the major sub-disciplines of science to produce a more complete representation of scientific domains and how they interact.

Library of congress subject heading (LCSH) browsing and natural language searching

Controlled topical vocabularies (CVs) are built into information systems to aid browsing and retrieval of items that may be unfamiliar, but it is unclear how this feature should be integrated with standard keyword searching. Few systems or scholarly prototypes have attempted this, and none have used the most widely used CV, the Library of Congress Subject Headings (LCSH), which organizes monograph collections in academic libraries throughout the world. This paper describes a working prototype of a Web application that concurrently allows topic exploration using an outline tree view of the LCSH hierarchy and natural language keyword searching of a real‐world Science and Engineering bibliographic collection. Pilot testing shows the system is functional, and work to fit the complex LCSH structure into a usable hierarchy is ongoing. This study contributes to knowledge of the practical design decisions required when developing linked interactions between topical hierarchy browsing and natural language searching, which promise to facilitate information discovery and exploration.

Spatialized information visualizations: a “BASSTEP” approach to application design

Large result sets stemming from topical queries on the Web tend to cause disorientation and are often reduced to a manageable size through successive exclusions (NOTing) and/or restrictions (ANDing) which also reject relevant documents. The information visualization (IV) technique known as spatialization is a scalable automatic process creating a topographical map metaphor of the semantic information space. The domain of IV offers many prototypes, some controlled experiments but few low-cost testing methods which are critical in the early stages of the design process. This communication reports on efforts to adapt the low-cost BASSTEP approach to the evaluation of the IV technique known as spatialization by isolating and evaluating (using paper mock-ups) information features of a spatialized Web corpus in the context of Web IR. Six (6) semi-structured formative interviews provide a list of most expected initial user interpretations of four (4) features and three (3) additional interviews attempt to triangulate the findings when these features are integrated into a single interface mock-up. This work hopes to verify if the application of the BASSTEP approach is applicable to spatialized visualisations early in the design process improving the usability of this visual IR tool.