waashk/acm huggingface dataset:
building information systems for mobile environments  it is expected that in the near future, tens of millions of users will have access to distributed information systems through wireless connections. the technical characteristics of the wireless medium and the resulting mobility of both data resources and data consumers raise new challenging questions regarding the development of information systems appropriate for mobile environments. in this paper, we report on the development of such a system. first, we describe the general architecture of the information system and the main considerations of our design. then, based on these considerations, we present our system support for maintaining the consistency of replicated data and for providing transaction schemas that account for the frequent but predictable disconnections, the mobility, and the vulnerability of the wireless environment.  evaggelia pitoura bharat bhargava
nested historical relations  the paper extends nested relations for managing temporal variation of complex objects. it combines the research in temporal databases and nested relations for nontraditional database applications. the basic modelling construct is a temporal atom as an attribute value. a temporal atom consists of two components, a value and temporal set which is a set of times denoting the validity period of the value. we define algebra operations for nested historical relations. data redundancy in nested historical relations is also discussed and criteria for well-structured nested relations are established.  a. u. tansel l. garnett
a novel checkpointing scheme for distributed database systems  we present a new checkpointing scheme for a distributed database system. our scheme records the states of some selected data items and can be executed at any time without stopping other activities in the database system. it makes use of "shadows" of data items to make sure that the collected data item values are "transaction-consistent". storage overhead is low, since at most one shadow is needed for each data item.  slawomir pilarski tiko kameda
multimedia document presentation, information extraction, and document formation in minos: a model and a system  minos is an object-oriented multimedia information system that provides integrated facilities for creating and managing complex multimedia objects. in this paper the model for multimedia documents supported by minos and its implementation is described. described in particular are functions provided in minos that exploit the capabilities of a modern workstation equipped with image and voice input- output devices to accomplish an active multimedia document presentation and browsing within documents. these functions are powerful enough to support a variety of office applications. also described are functions provided for the extraction of information from multimedia documents that exist in a large repository of information (multimedia document archiver) and functions that select and transform this information. facilities for information sharing among objects of the archiver are described; an interactive multimedia editor that is used for the extraction and interactive creation of new information is outlined; finally, a multimedia document formatter that is used to synthesize a new multimedia document from extracted and interactively generated information is presented.  this prototype system runs on a sun-3 workstation running unix'". an instavox, directly addressable, analog device is used to store voice segments.  s. christodoulakis m. theodoridou f. ho m. papa a. pathria
inquiry with imagery: historical archive retrieval with digital cameras  this paper describes an integration of geographic information systems (gis) and multimedia technologies to transform the ways k-12 students learn about their local communities. we have augmented a digital camera with a global positioning system (gps) and a digital compass to record its position and orientation when pictures are taken. the metadata are used to retrieve and present historical images of the photographed locations to students. another set of tools allows them to annotate and compare these historical images to develop explanations of how and why their communities have changed over time. we describe the camera architecture and learning outcomes that we expect to see in classroom use.  brian k. smith erik blankinship alfred ashford michael baker timothy hirzel
bringing order to the web: automatically categorizing search results  we developed a user interface that organizes web search results into hierarchical categories. text classification algorithms were used to automatically classify arbitrary search results into an existing category structure on-the-fly. a user study compared our new category interface with the typical ranked list interface of search results. the study showed that the category interface is superior both in objective and subjective measures. subjects liked the category interface much better than the list interface, and they were 50% faster at finding information that was organized into categories. organizing search results allows users to focus on items in categories of interest rather than having to browse through all the results sequentially.  hao chen susan dumais
delays and temporal incoherence due to the mediated status-status mappings the paper describes how the identification of 'status-status mappings' early in the specification and design of an interactive system can highlight potential temporal problems in the interface. these problems arise because without infinitely fast computation and communication, any constraints between status in the interface are bound to be violated some of the time. this violation will at best be a slight lag between the source of a change and its display and at worst may lead to inconsistency between parts of the interface. we identify the ways in which status-status mappings are violated and the way in which they are mediated by events in the implementation of a system. this enables the designer to control the eventual behaviour of the system and avoid the worst pitfalls. alan dix gregory abowd
datasplash  database visualization is an area of growing importance as database systems become larger and more accessible. datasplash is an easy-to- use, integrated environment for navigating, creating, and querying visual representations of data. we will demonstrate the three main components which make up the datasplash environment: a navigation system, a direct-manipulation interface for creating and modifying visualizations, and a direct-manipulation visual query system.  chris olston allison woodruff alexander aiken michael chu vuk ercegovac mark lin mybrid spalding michael stonebraker
a performance analysis of view materialization strategies  the conventional way to process commands for relational views is to use query modification to translate the commands into ones on the base relations. an alternative approach has been proposed recently, whereby materialized copies of views are kept, and incrementally updated immediately after each modification of the database. a related scheme exists, in which update of materialized views is deferred until just before data is retrieved from the view. a performance analysis is presented comparing the cost of query modification, immediate view maintenance, and deferred view maintenance. three different models of the structure of views are given a simple selection and projection of one relation, the natural join of two relations, and an aggregate (e.g. the sum of values in a column) over a selection-projection view. the results show that the choice of the most efficient view maintenance method depends heavily on the structure of the database, the view definition, and the type of query and update activity present.  eric n. hanson
impact of video frame rate on communicative behaviour in two and four party groups  there has been relatively little research on the impact of different levels of video quality on users of multimedia communication systems. this paper describes a study examining the impact of two levels of video frame rate on pairs and groups of four engaged on a design task, looking at one particular aspect of communication, namely reference. it was found that a low frame rate made speakers more communicatively cautious, using longer descriptions and more elaborations to refer to pictures used in the task, possibly as a result of being less certain that they had been understood. this only occurred in the two party groups despite a prediction that groups of four would be affected most by the frame rate manipulation. this study shows that video quality can have subtle effects on communication and that identical levels of quality may have different effects depending on the situation.  matthew jackson anne h. anderson rachel mcewan jim mullin
confronting the assumptions underlying the management of knowledge: an agenda for understanding and investigating knowledge management knowledge and knowledge management are receiving tremendous interest from both practitioners and academics. although knowledge management is often accepted as a very useful organizational activity, a number of the assumptions underlying knowledge management have not been investigated. this paper examines four knowledge management assumptions: knowledge is worth managing, organizations benefit from managing knowledge, knowledge can be managed, and little risk is associated with managing knowledge. the assumptions are analyzed at strategic and operational levels, and both negating and supporting evidence is presented. based on this analysis, a framework for research in knowledge management is proposed. the framework is used to generate a number of key questions that should be addressed in knowledge management research. particular attention is given to goals and rewards as well as to the role of information technology in knowledge management. kathy a. stewart richard baskerville veda c. storey james a. senn arjan raven cherie long
alternatives: exploring information appliances through conceptual design proposals  as a way of mapping a design space for a project on information appliances, we produced a workbook describing about twenty conceptual design proposals. on the one hand, they serve as suggestions that digital devices might embody values apart from those traditionally associated with functionality and usefulness. on the other, they are examples of research through design, balancing concreteness with openness to spur the imagination, and using multiplicity to allow the emergence of a new design space. here we describe them both in terms of content and process, discussing first the values they address and then how they were crafted to encourage a broad discussion with our partners that could inform future stages of design.  bill gaver heather martin
efficient and tumble similar set retrieval  set value attributes are a concise and natural way to model complex data sets. modern object relational systems support set value attributes and allow various query capabilities on them. in this paper we initiate a formal study of indexing techniques for set value attributes based on similarity, for suitably defined notions of similarity between sets. such techniques are necessary in modern applications such as recommendations through collaborative filtering and automated advertising. our techniques are probabilistic and approximate in nature. as a design principle we create structures that make use of well known and widely used data structuring techniques, as a means to ease integration with existing infrastructure.  we show how the problem of indexing a collection of sets based on similarity can be reduced to the problem of indexing suitably encoded (in a way that preserves similarity) binary vectors in hamming space thus, reducing the problem to one of similarity query processing in hamming space. then, we introduce and analyze two data structure primitives that we use in cooperation to perform similarity query processing in a hamming space. we show how the resulting indexing technique can be optimized for properties of interest by formulating constraint optimization problems based on the space one is willing to devote for indexing. finally we present experimental results from a prototype implementation of our techniques using real life datasets exploring the accuracy and efficiency of our overall approach as well as the quality of our solutions to problems related to the optimization of the indexing scheme.  aristides gionis dimitrios gunopulos nick koudas
selectivity estimation in spatial databases  selectivity estimation of queries is an important and well-studied problem in relational database systems. in this paper, we examine selectivity estimation in the context of geographic information systems, which manage spatial data such as points, lines, poly-lines and polygons. in particular, we focus on point and range queries over two-dimensional rectangular data. we propose several techniques based on using spatial indices, histograms, binary space partitionings (bsps), and the novel notion of spatial skew. our techniques carefully partition the input rectangles into subsets and approximate each partition accurately. we present a detailed experimental study comparing the proposed techniques and the best known sampling and parametric techniques. we evaluate them using synthetic as well as real-life tiger datasets. based on our experiments, we identify a bsp based partitioning that we call min- skew which consistently provides the most accurate selectivity estimates for spatial queries. the min-skew partitioning can be constructed efficiently, occupies very little space, and provides accurate selectivity estimates over a broad range of spatial queries.  swarup acharya viswanath poosala sridhar ramaswamy
browsing the structure of multimedia stories  stories may be analyzed as sequences of causally-related events and reactions to those events by the characters. we employ a notation of plot elements, similar to one developed by lehnert,and we extend that by forming higher level ``story threads''  stories may be analyzed as sequences of causally-related events and reactions to those events by the characters. we employ a notation of plot elements, similar to one developed by lehnert,and we extend that by forming higher level ``story threads''we apply the browser to corduroy, a children's short feature which was analyzed in detail. we provide additional illustrations with analysis of kiss of death, a film noir classic. effectively, the browser provides a framework for interactive summaries, video of the narrative  robert b. allen jane acheson
the spatial metaphor for user interfaces: experimental tests of reference by location versus name  the enduring dichotomy between spatial and symbolic modes of representation and retrieval acquires an added pragmatic dimension through recent developments in computer-based information retrieval. the standard name-based approach to object reference is now supplemented on some systems by a spatial alternative-often driven by an office or desktop metaphor. little rigorous evidence is available, however, to support the supposition that spatial memory in itself is more effective than symbolic memory.  the accuracy of spatial versus symbolic reference was assessed in three experiments. in experiment 1 accuracy of location reference in a location-only filing condition was initially comparable to that in a name-only condition, but deteriorated much more rapidly with increases in the number of objects filed. in experiment 2 subjects placed objects in a two- dimensional space containing landmarks (drawings of a desk, table, filing cabinets, etc.) designed to evoke an office metaphor, and in experiment 3 subjects placed objects in an actual, three-dimensional mock office. neither of these enhancements served to improve significantly the accuracy of location reference, and performance remained below that of a name-only condition in experiment 1. the results raise questions about the utility of spatial metaphor over symbolic filing and highlight the need for continuing research in which considerations of technological and economic feasibility are balanced by considerations of psychological utility.  william p. jones susan t. dumais
a framework for expressing and combining preferences  the advent of the world wide web has created an explosion in the available on- line information. as the range of potential choices expand, the time and effort required to sort through them also expands. we propose a formal framework for expressing and combining user preferences to address this problem. preferences can be used to focus search queries and to order the search results. a preference is expressed by the user for an entity which is described by a set of named fields; each field can take on values from a certain type. the * symbol may be used to match any element of that type. a set of preferences can be combined using a generic combine operator which is instantiated with a value function, thus providing a great deal of flexibility. same preferences can be combined in more than one way and a combination of preferences yields another preference thus providing the closure property. we demonstrate the power of our framework by illustrating how a currently popular personalization system and a real-life application can be realized as special cases of our framework. we also discuss implementation of the framework in a relational setting.  rakesh agrawal edward l. wimmers
extracting usability information from user interface events  modern window-based user interface systems generate user interface events as natural products of their normal operation. because such events can be automatically captured and because they indicate user behavior with respect to an application's user interface, they have long been regarded as a potentially fruitful source of information regarding application usage and usability. however, because user interface events are typically voluminos and rich in detail, automated support is generally required to extract information at a level of abstraction that is useful to investigators interested in analyzing application usage or evaluating usability. this survey examines computer-aided techniques used by hci practitioners and researchers to extract usability- related information from user interface events. a framework is presented to help hci practitioners and researchers categorize and compare the approaches that have been, or might fruitfully be, applied to this problem. because many of the techniques in the research literature have not been evaluated in practice, this survey provides a conceptual evaluation to help identify some of the relative merits and drawbacks of the various classes of approaches. ideas for future research in this area are also presented. this survey addresses the following questions: how might user interface events be used in evaluating usability? how are user interface events related to other forms of usability data? what are the key challenges faced by investigators wishing to exploit this data? what approaches have been brought to bear on this problem and how do they compare to one another? what are some of the important open research questions in this area?  david m. hilbert david f. redmiles
probabilistic document indexing from relevance feedback data  based on the binary independence indexing model, we apply three new concepts for probabilistic document indexing from relevance feedback data:  abstraction from specific terms and documents, which overcomes the restriction of limited relevance information for parameter estimation.  flexibility of the representation, which allows the integration of new text analysis and knowledge-based methods in our approach as well as the consideration of more complex document structures or different types of terms (e.g. single words and noun phrases).  probabilistic learning or classification methods for the estimation of the indexing weights making better use of the available relevance information.  we give experimental results for five test collections which show improvements over other indexing methods.  n. fuhr c. buckley
towards robust distributed systems (abstract)  current distributed systems, even the ones that work, tend to be very fragile: they are hard to keep up, hard to manage, hard to grow, hard to evolve, and hard to program. in this talk, i look at several issues in an attempt to clean up the way we think about these systems. these issues include the fault model, high availability, graceful degradation, data consistency, evolution, composition, and autonomy.  these are not (yet) provable principles, but merely ways to think about the issues that simplify design in practice. they draw on experience at berkeley and with giant-scale systems built at inktomi, including the system that handles 50% of all web searches.  eric a. brewer
uc berkeley's digital library project  for digital libraries to succeed, we must abandon the traditional notion of "library" altogether. the reason is as follows: the digital "library" will be a collection of distributed information services; producers of material will make it available, and consumers will find it and use it, perhaps through the help of automated agents. libraries in the traditional sense are nowhere to be found in this model (i. e., the notion of a limited intermediary containing some small fraction of preselected material available only to local patrons is replaced by a system providing to users everywhere direct access to the full contents of all available material).  robert wilensky
video scouting demonstration: smart content selection and recording  smart video content selection and recording is the best selling feature of the current personal tv receivers like tivo. these devices operate at the tv program level in that they use electronic program guides and user's program personal preferences to help consumers record and watch programs that match their interests. in this video scouting demonstration, we present a system that allows for the filtering and retrieving of tv sub-programs based on user's content preferences. the filtering process is realized via real-time video, audio, and transcript analysis. the demonstrator personalizes the tv experience in the areas of celebrity and financial information. the technology can translate into differentiating storage and set-top box product features for finding your favorite actors, most interesting personalized financial news of the day, commercial compaction and enhancement, and content augmentation with other sources of information such as web pages and encyclopedia. the demonstrator also reflects our active involvement in the mpeg-7 standard (content description interface).  nevenka dimitrova lalitha agnihotri george marmaropoulos thomas mcgee serhan dagtas