waashk/acm huggingface dataset:
webview materialization  a _webview_ is a web page automatically created from base data typically stored in a dbms. given the multi-tiered architecture behind database-backed web servers, we have the option of materializing a webview inside the dbms, at the web server, or not at all, always computing it on the fly (virtual). since webviews must be up to date, materialized webviews are immediately refreshed with every update on the base data. in this paper we compare the three materialization policies (materialized inside the dbms, materialized at the web server and virtual) analytically, through a detailed cost model, and quantitatively, through extensive experiments on an implemented system. our results indicate that materializing at the web server is a more scalable solution and can facilitate an order of magnitude more users than the virtual and materialized inside the dbms policies, even under high update workloads.  alexandros labrinidis nick roussopoulos
comparison of empirical testing and walkthrough methods in user interface evaluation  we investigated the relative effectiveness of empirical usability testing and individual and team walkthrough methods in identifying usability problems in two graphical user interface office systems. the findings were replicated across the two systems and show that the empirical testing condition identified the largest number of problems, and identified a significant number of relatively severe problems that were missed by the walkthrough conditions. team walkthroughs achieved better results than individual walkthroughs in some areas. about a third of the significant usability problems identified were common across all methods. cost- effectiveness data show that empirical testing required the same or less time to identify each problem when compared to walkthroughs.  claire-marie karat robert campbell tarra fiegel
on the content of materialized aggregate views  we consider the problem of answering queries using only materialized views. we first show that if the views subsume the query from the point of view of the information content, then the query can be answered using only the views, but the resulting query might be extremely inefficient. we then focus on aggregate views and queries over a single relation, which are fundamental in many applications such as data warehousing. we show that in this case, it is possible to guarantee that as soon as the views subsume the query, it can be completely rewritten in terms of the views in a simple query language. our main contribution is the conception of various rewriting algorithms which run in polynomial time, and the proof of their completeness which relies on combinatorial arguments. finally, we discuss the choice of materializing or not ratio views such as average and percentage, important for the design of materialized views. we show that it has an impact on the information content, which can be used to protect data, as well as on the maintenance of views.  stephane grumbach leonardo tininini
using a theoretical multimedia taxonomy framework  multimedia (mm) is a polysemous term, a term with many definitions, and in this case, many roots. in this paper, multimedia is defined as the seamless integration of two or more media. each ancestor brings another requirement, muddying the field and making it difficult to work through. a multimedia taxonomy based on a previous media taxonomy is proposed to help organize the discipline. the taxonomy helps to classify the space called multimedia and to draw attention to difficult issues. the paper outlines the forms contributing to multimedia---text, sound, graphics, and motion---and aligns them with probable formats---elaboration, representation, and abstraction--- and sets them within a context---audience, discipline, interactivity, quality, usefulness, and aesthetics. the contexts are more clearly defined in two areas: interactivity and the information basis for a discipline. examples are presented describing the use of the taxonomy in the design and evaluation of student projects in a computer science-based multimedia course.  rachelle s. heller c. dianne martin nuzi haneef sonja gievska-krliu
the goms family of user interface analysis techniques: comparison and contrast  sine the publication of the psychology of human- computer interaction, the goms model has been one of the most widely known theoretical concepts in hci. this concept has produced severval goms analysis techniques that differ in appearance and form, underlying architectural assumptions, and predictive power. this article compares and contrasts four popular variantsof the goms family (the keystroke-level model, the original goms formulation, ngomsl, and cpm-goms) by applying them to a single task example.  bonnie e. john david e. kieras
searching for unity among diversity: exploring the "interface" concept  despite widespread interest in the human-computer interaction (hci) field, there remains much debate as to appropriate conceptual frameworks for the field, and even confusion surrounding the meaning of basic terms in the field. hci is seen by many as focusing on the design of interfaces to computer systems, yet exactly what is implied by this focus on "interfaces" is unclear. in this paper we show how a better understanding of what is meant by the interface is possible via the concept of abstraction levels. we show how this levels approach can clarify some ambiguities, and also how it can be related to different phases in the evolution of the human-computer interaction field itself. in this context, we are able to account for the recent interest in activity theory as a possible alternative framework for hci work, while stressing the need for hci research and design to consider each of the separate, but related, levels.  kari kuutti liam j. bannon
dynamic digital libraries for children  the majority of current digital libraries (dls) are not designed forchildren. for dls to be popular with children, they need to be fun, easy-to-use and empower them, whether as readers or authors. this paper describes a new childrens dl emphasizing its design and evaluation, working with the children (11-14 year olds) as design partners and testers. a truly participatory process was used, and observational study was used as a means of refinement to the initial design of the dl prototype. in contrast with current dls, the childrens dl provides both a static as well as a dynamic environment to encourage active engagement of children in using it. design, implementation and security issues are also raised.  yin leng theng norliza mohd-nasir george buchanan bob fields harold thimbleby noel cassidy
query processing in the objectstore database system  objectstore is an object-oriented database system supporting persistence orthogonal to type, transaction management, and associative queries. collections are provided as objects. the data model is non-1nf, as objects may have embedded collections. queries are integrated with the host language in the form of query operators whose operands are a collection and a predicate. the predicate may itself contain a (nested) query operating on an embedded collection. indexes on paths may be added and removed dynamically. collections, being treated as objects, may be referred to indirectly, e.g., through a by-reference argument. for this reason and others, multiple execution strategies are generated, and a final selection is made just prior to query execution. nested queries can result in interleaved execution and strategy selection.  jack orenstein sam haradhvala benson margulies don sakahara
predicting document access in large multimedia repositories  network- accessible multimedia databases, repositories, and libraries are proliferating at a rapid rate. a crucial problem for these repositories remains timely and appropriate document access. in this article, we borrow a model from psychological research on human memory, which has long studied retrieval of memory items based on frequency and recency rates of past item occurrences. specifically, the model uses frequency and recency rates of prior document accesses to predict future document requests. the model is illustrated by analyzing the log file of document accesses to the georgia institute of technology world wide web (www) repository, a large multimedia respository exhibiting high access rates. results show that the model predicts document access rates with a reliable degree of accuracy. we describe extensions to the basic approach that combine the recency and frequency analyses and which incorporate respository structure and document type. these results have implications for the formulation of descriptive user models of information access in large repositories. in addition, we sketch applications in the areas of design of information systems and interfaces and their document-caching algorithms.  margaret m. recker james e. pitkow
empirical results on locality in database referencing  database referencing behaviour is analyzed with respect to locality features. the analysis is based on database reference strings collected from several runs of typical batch programs accessing a real database. locality of reference is measured by the stack distance probability distribution, the number of block faults, and a locality measure based on the memory reservation size.  in all the experiments, locality of reference is observed, but it is found to be weaker than in code referencing or even in some previous studies on database referencing. the phase/transition concept used in virtual memory systems is not well applicable to database referencing, since a large part of the locality set is constantly changing. the disruption of the phases is predominantly due to random referencing of data blocks. the references to index blocks show stronger locality. in some special cases, sequentiality is observed in the use of the data blocks. in general, neither replacement strategies developed for virtual memory systems nor prefetching techniques seem adequate for performance improvement of database referencing.  a. inkeri verkamo
hierarchies and relative operators in the olap environment  in the last few years, numerous proposals for modelling and querying multidimensional databases (mddb) are proposed. a rigorous classification of the different types of hierarchies is still an open problem. in this paper we propose and discuss some different types of hierarchies within a single dimension of a cube. these hierarchies divide in different levels of aggregation a single dimension. depending on them, we discuss the characterization of some olap operators that refer to hierarchies in order to maintain the data cube consistency. moreover, we propose a set of operators for changing the hierarchy structure. the issues discussed provide modelling flexibility during the scheme design phase and correct data analysis.  elaheh pourabbas maurizio rafanelli
assessing the climate for change: a methodology for managing human factors in a computerized information system implementation  it is now well established that computers and other information technologies are instruments of organizational change. that is, successful implementation of an information system will change the way in which organizational members do their work. there is an extensive literature on social change which characterizes the change process and how to manage it. in particular, there is a subset of this literature which concerns the implementation of computerized information systems  david g. hopelain
linear approximation of planar spatial databases using transitive-closure logic  we consider spatial databases in the plane that can be defined by polynomial constraint formulas. motivated by applications in geographic information systems, we investigate linear approximations of spatial databases and study in which language they can be expressed effectively. specifically, we show that they cannot be expressed in the standard first-order query language for polynomial constraint databases but that an extension of this first-order language with transitive closure suffices to express the approximation query in an effective manner. furthermore, we introduce an extension of transitive- closure logic and show that this logic is complete for the computable queries on linear spatial databases. this result together with our first result implies that this extension of transitive-closure logic can express all computable topological queries on arbitrary spatial databases in the plane.  floris geerts bart kuijpers
graph-based object-oriented approach for structural and behavioral representation of multimedia data  the management of multimedia information poses special requirements for multimedia information systems. both representation and retrieval of the complex and multifaceted multimedia data are not easily handled with the flat relational model and require new data models. in the last several years, object-oriented and graph-based data models are actively pursued approaches for handling the multimedia information. in this paper the characteristics of the novel graph-based object-oriented data model are presented. this model represents the structural and behavioral aspects of data that form multimedia information systems. it also provides for handling the continuously changing user requirements and the complexity of the schema and data representation in multimedia information systems using the schema versioning approach and perspective version abstraction.  ivan radev niki pissinou kia makki e. k. park
"it's infrastructure all the way down" (keynote address)  what is infrastructure and how shall we know it? as libraries move partly to desktops, one of the challenges facing the digital library community becomes designing for distributed use across many kinds of local circumstance. these circumstances vary widely in terms of people, resources, support, and technical configurations. designing for this variety means reconceptualizing "user meets screen" as "user meets infrastructure." this requires scaling up traditional design and evaluation methods, as well as a richer knowledge of the organizational and historical contexts of use. this talk addresses some of the methodological challenges involved in such work.  susan leigh star (leigh) is professor of communication at the university of california, san diego. she received her ph.d in sociology of science and medicine from uc san francisco. before coming to ucsd in 1999, she was professor of information science at the university of illinois, urbana- champaign. she has also taught at uc irvine and keele university, in england, and several universities in scandinavia as guest professor. much of her research has been on the social implications and design of large-scale technology, especially information technology. among her publications are "the cultures of computing" (ed) (blackwell, 1995), "regions of the mind: brain research and the quest for scientific certainty" (stanford 1989), and (with geoffrey bowker), "sorting things out: classification and its consequences" (mit, 1999). she is volume editor for science and technology for the women's studies international encyclopedia (edited by cheris kramarae and dale spender), forthcoming from routledge in 2000. her current research concerns ethical and methodological dilemmas in on-line research with human subjects.  susan leigh star
security-control methods for statistical databases: a comparative study  this paper considers the problem of providing security to statistical databases against disclosure of confidential information. security-control methods suggested in the literature are classified into four general approaches: conceptual, query restriction, data perturbation, and output perturbation.  criteria for evaluating the performance of the various security-control methods are identified. security-control methods that are based on each of the four approaches are discussed, together with their performance with respect to the identified evaluation criteria. a detailed comparative analysis of the most promising methods for protecting dynamic- online statistical databases is also presented.  to date no single security-control method prevents both exact and partial disclosures. there are, however, a few perturbation-based methods that prevent exact disclosure and enable the database administrator to exercise "statistical disclosure control." some of these methods, however introduce bias into query responses or suffer from the 0/1 query-set-size problem (i.e., partial disclosure is possible in case of null query set or a query set of size 1).  we recommend directing future research efforts toward developing new methods that prevent exact disclosure and provide statistical- disclosure control, while at the same time do not suffer from the bias problem and the 0/1 query- set-size problem. furthermore, efforts directed toward developing a bias- correction mechanism and solving the general problem of small query-set-size would help salvage a few of the current perturbation- based methods.  nabil r. adam john c. worthmann
knowledgebase transformations  we propose a language that expresses uniformly queries and updates on knowledgebases consisting of finite sets of relational structures. the language contains an operator that "inserts" arbitrary first-order sentences into knowledgebase. the semantics of the insertion is based on the notion of update formalized by katsuno and mendelzon in the context of belief revision theory. our language can express, among other things, hypothetical queries and queries on recursively indefinite databases. the expressive power of our language lies between existential second-order and general second-order queries. the data complexity is in general within exponential time, although it can be lowered to co-np and to polynomial time by restricting the form of queries and updates.  gösta grahne alberto o. mendelzon peter z. revesz
content-based browsing of video sequences  a novel methodology to represent the contents of a video sequence is presented. the representation is used to allow the user to rapidly view a video sequence in order to find a particular point within the sequence and/or to decide whether the contents of the sequence are relevant to his or her needs. this system, referred to as content-based browsing, forms an abstraction to represent each shot of the sequence by using a representative frame, or an rframe, and it includes management techniques to allow the user to easily navigate the rframes. this methodology is superior to the current techniques of fast forward and rewind because rather than using every frame to view and judge the contents, only a few abstractions are used. therefore, the need to retrieve the video from a storage system and to transmit every frame over the network in its entirety no longer exists, saving time, expenses, and bandwidth.  f. arman r. depommier a. hsu m.-y. chiu
information organization using rufus  computer system users today are inundated with a flood of semi-structured information, such as documents, electronic mail, programs, and images. today, this information is typically stored in filesystems that provide limited support for organizing, searching, and operating upon this data, all operations that are vital to the ability of users to effectively use this data. database systems provide good function for organizing, searching, managing and writing applications on structured data. current database systems are inappropriate for semi-structured information because moving the data into the database breaks all existing applications that use the data. the rufus system attacks the problems of semi-structured information by using database function to help users manage semi-structured information without requiring that the user's information reside in the database.  allen luniewski peter schwarz kurt shoens jim stamos john thomas
a federated architecture for information management  an approach to the coordinated sharing and interchange of computerized information is described emphasizing partial, controlled sharing among autonomous databases. office information systems provide a particularly appropriate context for this type of information sharing and exchange. a federated database architecture is described in which a collection of independent database systems are united into a loosely coupled federation in order to share and exchange information. a federation consists of components (of which there may be any number) and a single federal dictionary. the components represent individual users, applications, workstations, or other components in an office information system. the federal dictionary is a specialized component that maintains the topology of the federation and oversees the entry of new components. each component in the federation controls its interactions with other components by means of an export schema and an import schema. the export schema specifies the information that a component will share with other components, while the import schema specifies the nonlocal information that a component wishes to manipulate. the federated architecture provides mechanisms for sharing data, for sharing transactions (via message types) for combining information from several components, and for coordinating activities among autonomous components (via negotiation). a prototype implementation of the federated database mechanism is currently operational on an experimental basis.  dennis heimbigner dennis mcleod
data base processor mage  in this paper, we present the design of data base processor mage. this dbp is based on a hierarchical db access method. it is composed of two microprocessors, a disk processor and a moving head disk. the processor requirements, design decisions, and architecture are discussed.  we start with an overview of dbp framework. the mage db access method is then summarized. finally, we present the design and implementation of the dbp, with a particular emphasis on the disk processor.  g. berger sabbatel
information design considerations for improving situation awareness in complex problem-solving  the conventional techniques for task analysis derive the basic tasks that make up user actions. however, in the complex-problem solving environment, attempts to describe step-by-step actions breakdown because no single route to a solution exists. although individual tasks can be defined, task-analysis normally results in the tasks being divorced from context. however, to support complex problem-solving, the design must place the information within the situation context and allow users to develop and maintain situation awareness.  michael j. albers
open decdtm: constraint based transaction management  open decdtm offers portable transaction management services layered on osf dce which support the application (tx), resource manager (xa), and transactional dce rpc (txrpc) interfaces specified by x/open. open decdtm also provides interoperability with osi transaction processing (osi tp) and openvms systems using the decdtm openvms protocol. protocols executed by open decdtm are specified by constraints. this simplifies the development of transactional gateways between different data transfer protocols and transaction models.  johannes klein francis upton
a computational model and classification framework for social navigation  social navigation is the process of making navigational decisions in real or virtual environments based on social and communicative interaction with others. a computational model for social navigation is presented as an extension to an existing framework for general navigation, reducing decision- making to the minimization of cognitive costs. consideration for social navigation gives rise to a classification framework based on the synchronicity, directness, and social presence during social interaction, each of which has direct effect on the cognitive costs of navigational tasks. finally, a new recommender system, trailguide, is presented as a tool that facilitates social navigation by allowing authors to explicitly publish "trails" within and between world wide web pages.  mark o. riedl