waashk/acm huggingface dataset:
adaptive precision setting for cached approximate values  caching approximate values instead of exact values presents an opportunity for performance gains in exchange for decreased precision. to maximize the performance improvement, cached approximations must be of appropriate precision: approximations that are too precise easily become invalid, requiring frequent refreshing, while overly imprecise approximations are likely to be useless to applications, which must then bypass the cache. we present a parameterized algorithm for adjusting the precision of cached approximations adaptively to achieve the best performance as data values, precision requirements, or workload vary. we consider interval approximations to numeric values but our ideas can be extended to other kinds of data and approximations. our algorithm strictly generalizes previous adaptive caching algorithms for exact copies: we can set parameters to require that all approximations be exact, in which case our algorithm dynamically chooses whether or not to cache each data value.  we have implemented our algorithm and tested it on synthetic and real-world data. a number of experimental results are reported, showing the effectiveness of our algorithm at maximizing performance, and also showing that in the special case of exact caching our algorithm performs as well as previous algorithms. in cases where bounded imprecision is acceptable, our algorithm easily outperforms previous algorithms for exact caching.  chris olston boon thau loo jennifer widom
the sift information dissemination system  information dissemination is a powerful mechanism for finding information in wide-area environments. an information dissemination server accepts long-term user queries, collects new documents from information sources, matches the documents against the queries, and continuously updates the users with relevant information. this paper is a retrospective of the stanford information filtering service (sift), a system that as of april 1996 was processing over 40,000 worldwide subscriptions and over 80,000 daily documents. the paper describes some of the indexing mechanisms that were developed for sift, as well as the evaluations that were conducted to select a scheme to implement. it also describes the implementation of sift, and experimental results for the actual system. finally, it also discusses and experimentally evaluates techniques for distributing a service such as sift for added performance and availability.  tak w. yan hector garcia-molina
a multi-view intelligent editor for digital video libraries  silver is an authoring tool that aims to allow novice users to edit di gital video. the goal is to make editing of digital video as easy as text editing. silver provides multiple coordinated views, including project, source, outline, subject, storyboard, textual transcript and timeline views. selections and edits in any view are synchronized with all other views. a variety of recognition algorithms are applied to the video and audio content and then are used to aid in the editing tasks. the informedia digital library supplies the recognition algorithms and metadata used to support intelligent editing, and informedia also provides search and a repository. the metadata includes shot boundaries and a time-synchronized transcript, which are used to support intelligent selection and intelligent cut/copy/paste.  brad a. myers juan p. casares scott stevens laura dabbish dan yocum albert corbett
project feelex: adding haptic surface to graphics  this paper presents work carried out for a project to develop a new interactive technique that combines haptic sensation with computer graphics. the project has two goals. the first is to provide users with a spatially continuous surface on which they can effectively touch an image using any part of their bare hand, including the palm. the second goal is to present visual and haptic sensation simultaneously by using a single device that doesn't oblige the user to wear any extra equipment. in order to achieve these goals, we designed a new interface device comprising of a flexible screen, an actuator array and a projector. the actuator deforms the flexible screen onto which the image is projected. the user can then touch the image directly and feel its shape and rigidity. initially we fabricated two prototypes, and their effectiveness is examined by studying the observations made by anonymous users and a performance evaluation test for spatial resolution.  hiroo iwata hiroaki yano fumitaka nakaizumi ryo kawamura
a hierarchical approach to concurrency control for multidatabases  a multidatabase system is a facility that allows access to data stored in multiple autonomous and possibly heterogeneous database systems. in order to support atomic updates across multiple database systems, a global concurrency control algorithm is required. hierarchical concurrency control has been proposed as one possible approach for multidatabase systems. however, to apply this approach, some restrictions have to be imposed on the local concurrency control algorithms. in this paper, we identify the restriction. based on this restriction, we formalize the hierarchical concurrency control approach and prove its correctness. a new global concurrency control algorithm based on this hierarchical approach is also presented.  yungho leu ahmed k. elmagarmid
a condensed representation to find frequent patterns  given a large set of data, a common data mining problem is to extract the frequent patterns occurring in this set. the idea presented in this paper is to extract a condensed representation of the frequent patterns called disjunction-free sets, instead of extracting the whole frequent pattern collection. we show that this condensed representation can be used to regenerate all frequent patterns and their exact frequencies. moreover, this regeneration can be performed without any access to the original data. practical experiments show that this representation can be extracted very efficiently even in difficult cases. we compared it with another representation of frequent patterns previously investigated in the literature called frequent closed sets. in nearly all experiments we have run, the disjunction-free sets have been extracted much more efficiently than frequent closed sets.  artur bykowski christophe rigotti
uniform generation in spatial constraint databases and applications (extended abstract)  we study the efficient approximation of queries in linear constraint databases using sampling techniques. we define the notion of an almost uniform generator for a generalized relation and extend the classical generator of dyer, frieze and kannan for convex sets to the union and the projection of relations. for the intersection and the difference, we give sufficient conditions for the existence of such generators. we show how such generators give relative estimations of the volume and approximations of generalized relations as the composition of convex hulls obtained from the samples.  david gross michel de rougemont
abstraction mechanisms for database programming  databases contain vast amounts of highly related data accessed by programs of considerable size and complexity. therefore, database programming has a particular need for high level constructs that abstract from details of data access, data manipulation, and data control.  the paper investigates the suitability of several well-known abstraction mechanisms for database programming (e.g., control abstraction and functional abstraction). in addition, it presents some new abstraction mechanisms (access abstraction and transactional abstraction) particularly designed to manage typical database problems like integrity and concurrency control.  joachim w. schmidt manuel mall
query transformation in an instructional database management system  a database management system designed for instructional use should offer facilities usually not required in a commercial environment. one of the most important features desirable in such a system is its ability to perform query transformation. the use of an universal symbol and tree manipulation system to perform query translation, decomposition and optimization is described in the paper. examples of transformation rules required to translate sql expressions into equivalent quel expressions, decompose sql expressions into parse trees and perform optimization of expressions based on relational algebra are shown.  an experimental relational dbms using the above approach is currently under development at the university of houston. it supports various nonprocedural query languages within a single system, using a unified database dictionary. cross-translation between various query languages is allowed. the results of every important phase of the query transformation during its execution are interactively available to the system user.  bogdan czejdo marek rusinkiewioz
indexing field values in field oriented systems: interval quadtree  with the extension of spatial database applications, field oriented systems emerge as an important research issue in order to deal with continuous natural phenomena during the last years. it however has a large volume of data and efficient indexing methods for field data are necessary to overcome the performance obstacle. in special, we introduce indexing methods for field value queries (i.e. searching some regions where the temperature is more 20 degrees). we introduce the concept of subfield and show how we make use of this concept to index field values in field oriented systems. we present two implementation methods based on quadtree space subdivision. we modify traditional linear quadtree implementation method for field value query processing using subfields. we analyze the performance of our methods. experimentation with real terrain data shows that proposed indexing methods improve the query processing time of field value queries in comparison with the case of no indexing method.  myoung-ah kang sylvie servigne ki-joune joune li robert laurini
database research at ipsi  at the integrated publication and information systems institute (ipsi) of the gmd (gesellschaft fur mathematik und datenverarbeitung) database research is focused towards distributed database management systems to support the integration of heterogeneous multi-media information bases needed in an integrated publishing environment. the objective is to investigate advanced object-oriented and active data modelling concepts together with the principles of distributed data stores and data management. the unifying basis for the database research is the object-oriented data model vml developed in the project vodak over the last four years. the data model is based on recursively defined meta classes, classes and instance hierarchies paired with a strict separation of structural and operational definitions in a polymorphic type system.  this report describes the highlights of the work on the vodak database system, the research efforts in heterogeneous database integration and the research plans of the multimedia database project as well as applications of our system in different environments such as hypertext and office automation.  erich neuhold volker turau
tutorial on data base machines  the cost of the hardware components that make up modern day digital computers continues to drop at a rapid rate. along with this cost reduction there exists a simultaneous increase in the number of components that one can place on an integrated circuit chip. this leads to what seems to be an ever decreasing cost of hardware combined with a continued increase in functional capability. when these improvements are coupled with the ever increasing costs of software, primarily caused by increased personnel costs, it becomes imperative to consider moving functions that are primarily executed in software, to hardware.  one field that has received increased attention vis-a-vis movement of software functions to hardware is the database management field. owing to size and complexity, managing databases becomes increasingly difficult. over the past few years, increasing efforts have been expended in the study of new types of hardware called database machines which are designed solely for the purpose of managing data. this research has been driven by the decreasing cost of hardware and by the need for performance improvements due to increased database size and complexity and a maturing database theory.  p. bruce berra
robust color indexing  in content based image retrieval, color indexing is one of the most prevalent retrieval methods. in literature, most of the attention has been focussed on the color model with little or no consideration of the noise models. in this paper we investigate the problem of color indexing from a maximum likelihood perspective. we take into account the color model, the noise distribution, and the quantization of the color features. furthermore, from the real noise distribution we derive a distortion measure, which consistently provides improved accuracy. our investigation concludes with results on a real stock photography database, consisting of 11,000 color images.  nicu sebe michael s. lew
a partial test of the task-medium fit proposition in a group support system environment  a laboratory experiment was carried out to partially test the task-medium fit proposition in a gss environment. communication medium was varied using a face-to-face gss and a dispersed gss setting. task type was varied using an intellective and a preference task. group decision outcome variables of interest were (actual and perceived) decision quality, decision time, decision satisfaction, and decision process satisfaction. with the intellective task, there were no significant differences between face-to-face gss and dispersed gss groups for all group decision outcome variables. with the preference task, face-to-face gss groups performed significantly better than dispersed gss groups for all group decision outcome variables. these findings suggest that group decision outcomes in a gss environment tend to be adversely affected when the communication medium is too lean for the task but not when the communication medium is too rich for the task. consequences of providing groups with too rich and too lean a communication medium for their task are discussed. implications of these findings, and other related results, for practice and for future revisions of media richness theory are explored.  bernard c. y. tan kwok-kee wei choon-ling sia krishnamurthy s. raman
a bucket architecture for the open video project  the open video project is a collection of public domain digital video available for research and other purposes. the open video collection currently consists of approximately 350 video segments, ranging in duration from 10 seconds to 1 hour. rapid growth for the collection is planned through agreements with other video repository projects and provision for user contribution of video. to handle the increased accession, we are experimenting with "buckets", aggregative intelligent publishing constructs for use in digital libraries.  michael l. nelson gary marchionini gary geisler meng yang
the web as a graph  the pages and hyperlinks of the world-wide web may be viewed as nodes and edges in a directed graph. this graph has about a billion nodes today, several billion links, and appears to grow exponentially with time. there are many reasons---mathematical, sociological, and commercial \---for studying the evolution of this graph. we first review a set of algorithms that operate on the web graph, addressing problems from web search, automatic community discovery, and classification. we then recall a number of measurements and properties of the web graph. noting that traditional random graph models do not explain these observations, we propose a new family of random graph models.  ravi kumar prabhakar raghavan sridhar rajagopalan d. sivakumar andrew tompkins eli upfal
soft machines: a philosophy of user-computer interface design  machines and computer systems differ in many characteristics that have important consequences for the user. machines are special-purpose, have forms suggestive of their functions, are operated with controls in obvious one-to- one correspondence with their actions, and the consequences of the actions on visible objects are immediately and readily apparent. by contrast, computer systems are general-purpose, have inscrutable form, are operated symbolically via a keyboard with no obvious correspondence between keys and actions, and typically operate on invisible objects with consequences that are not immediately or readily apparent. the characteristics possessed by machines, but typically absent in computer systems, aid learning, use and transfer among machines. but "hard," physical machines have limitations: they are inflexible, and their complexity can overwhelm us. we have built in our laboratory "soft machine" interfaces for computer systems to capitalize on the good characteristics of machines and overcome their limitations. a soft machine is implemented using the synergistic combination of real-time computer graphics to display "soft controls," and a touch screen to make soft controls operable like conventional hard controls.  lloyd h. nakatani john a. rohrlich
visual search and mouse-pointing in labeled versus unlabeled two-dimensional visual hierarchies an experiment investigates (1) how the physical structure of a computer screen layout affects visual search and (2) how people select a found target object with a mouse. two structures are examined---labeled visual hierarchies (groups of objects with one label per group) and unlabeled visual hierarchies (groups without labels). search and selection times were separated by imposing a point-completion deadline that discouraged participants from moving the mouse until they found the target. the observed search times indicate that labeled visual hierarchies can be searched much more efficiently than unlabeled visual hierarchies, and suggest that people use a fundamentally different strategy for each of the two structures. the results have implications for screen layout design and cognitive modeling of visual search. the observed mouse-pointing times suggest that people use a slower and more accurate speed-accuracy operating characteristic to select a target with a mouse when visual distractors are present, which suggests that fitts' law coefficients derived from standard mouse-pointing experiments may under- predict mouse-pointing times for typical human-computer interactions. the observed mouse-pointing times also demonstrate that mouse movement times for a two-dimensional pointing task can be most-accurately predicted by setting the _w_ in fitts' law to the width of the target along the line of approach. anthony j. hornof
beyond the graphical user interface (abstract)  the wildly popular graphical user interfaces are a dramatic improvement over earlier interaction styles, but the next generation of user interfaces is already being fashioned. the future will be dynamic, spatial, gestural, colorful, ubiquitous, often auditory, and sometimes virtual. the dominance of visual information with hi- res images and full-motion video will push the hardware requirements, absorb network capacity, and challenge the algorithm designers. as human-computer interaction researchers accumulate experimental data and theory matures, novel input devices, information visualization displays, and interaction strategies will emerge.  ben shneiderman
argo: a system for distributed collaboration  the goal of the argo system is to allow medium-sized groups of users to collaborate remotely from their desktops in a way that approaches as closely as possible the effectiveness of face-to-face meetings. in support of this goal, argo combines high quality multi-party digital video and full-duplex audio with telepointers, shared applications, and whiteboards in a uniform and familiar environment. the shared applications can be unmodified x programs shared via a proxy server, unmodified groupware applications, and applications written using our toolkit. workers can contact each other as easily as making a phone call, and can easily bring into a conference any material they are working on. they do so by interacting with an object-oriented, client/server conference control system. the same conference control system is used to support teleporting, i.e. moving the desktop environment from one workstation's display to another (for example, from office to home). this paper describes the system we have built to test the hypothesis that the effectiveness of remote collaboration can be substantially impacted by the responsiveness of the interaction media.  h. gajewska j. kistler m. manasse d. redell
the impact of fluid documents on reading and browsing: an observational study  fluid documents incorporate additional information into a page by adjusting typography using interactive animation. one application is to support hypertext browsing by providing glosses for link anchors. this paper describes an observational study of the impact of fluid documents on reading and browsing. the study involved six conditions that differ along several dimensions, including the degree of typographic adjustment and the distance glosses are placed from anchors. six subjects read and answered questions about two hypertext corpora while being monitored by an eyetracker. the eyetracking data revealed no substantial differenccs in eye behavior between conditions. gloss placement was significant: subjects required less time to use nearby glosses. finally, the reaction to the conditions was highly varied, with several conditions receiving both a best and worst rating on the subjective questionnaires. these results suggest implications for the design of dynamic reading environments.  polle t. zellweger susan harkness regli jock d. mackinlay bay-wei chang
patterns of contact and communication in scientific research collaboration  in this paper, we describe the influence of physical proximity on the development of collaborative relationships between scientific researchers and on the execution of their work. our evidence is drawn from our own studies of scientific collaborators, as well as from observations of research and development activities collected by other investigators. these descriptions provide the foundation for a discussion of the actual and potential role of communications technology in professional work, especially for collaborations carried out at a distance.  robert kraut carmen egido jolene galegher
data-valued partitioning and virtual messages (extended abstract)  network partition failures in traditional distributed databases cause severe problems for transaction processing. the only way to overcome the problems of "blocking" behavior for transaction processing in the event of such failures is, effectively, to execute them at single sites. a new approach to data representation and distribution is proposed and it is shown to be suitable for failure-prone environments. we propose techniques for transaction processing, concurrency control and recovery for the new representation. several properties that arise as a result of these methods, such as non-blocking behavior, independent recovery and high availability, suggest that the techniques could be profitably implemented in a distributed environment.  nandit soparkar abraham silberschatz