waashk/acm huggingface dataset:
eddies: continuously adaptive query processing  in large federated and shared-nothing databases, resources can exhibit widely fluctuating characteristics. assumptions made at the time a query is submitted will rarely hold throughout the duration of query processing. as a result, traditional static query optimization and execution techniques are ineffective in these environments.  in this paper we introduce a query processing mechanism called an _eddy_, which continuously reorders operators in a query plan as it runs. we characterize the _moments of symmetry_ during which pipelined joins can be easily reordered, and the _synchronization barriers_ that require inputs from different sources to be coordinated. by combining eddies with appropriate join algorithms, we merge the optimization and execution phases of query processing, allowing each tuple to have a flexible ordering of the query operators. this flexibility is controlled by a combination of fluid dynamics and a simple learning algorithm. our initial implementation demonstrates promising results, with eddies performing nearly as well as a static optimizer/executor in static scenarios, and providing dramatic improvements in dynamic execution environments.  ron avnur joseph m. hellerstein
summary of database research activities at the university of massachusetts, amherst  at the university of massachusetts, we have been conducting research in the following database related areas: theoretical support for database system development, database programming languages, flexible concurrency control and transaction management, real-time databases, and information retrieval. the following is a summary of our research in each area.  k. ramamritham e. moss j. a. stankovic d. stemple b. croft d. towsley
using the baby-babble-blanket for infants with motor problems: an empirical study  children with motor problems often develop to be passive, presumably because of an inability to communicate and to control the environment. the baby- babble-blanket (bbb), a pad with pressure switches linked to a macintosh computer, was developed to meet this need. lying on the pad, infants use head- rolling, leg-lifting and kicking to produce digitized sound. data is collected by the bbb software on the infant's switch activations. an empirical study was carried out on a five-month-old infant with club feet, hydrocephaly and poor muscle tone to determine what movements the infant could use to access the pad, whether movements would increase over a baseline in response to sound, and what level of cause and effect the infant would demonstrate. videotapes and switch activation data suggest that the infant:  1) could activate the device by rolling his head and raising his legs.  2) increased switch activations, over a no-sound baseline, in response to the sound of his mother's voice.  3) was able to change from using his head to raising his legs in response to the reinforcer.  h. j. fell h. delta r. peterson l. j. ferrier z. mooraj m. valleau
storhouse metanoia - new applications for database, storage & data warehousing  this paper describes the storhouse/relational manager (rm) database system that uses and exploits an _active storage hierarchy_. by active storage hierarchy, we mean that storhouse/rm executes sql queries _directly_ against data stored on all hierarchical storage (i.e. disk, optical, and tape) without post processing a file or a dba having to manage a data set. we describe and analyze storhouse/rm features and internals. we also describe how storhouse/rm differs from traditional hsm (hierarchical storage management) systems. for commercial applications we describe an evolution to the data warehouse concept, called _atomic data store_, whereby atomic data is stored in the database system. atomic data is defined as storing _all_ the historic data values and executing queries against them. we also describe a _hub-and-spoke data warehouse architecture_, which is used to feed or fuel data into data marts.  furthermore, we provide analysis how storhouse/rm can be _federated_ with db2, oracle and microsoft sql server 7 (ss7) and thus provide these databases an active storage hierarchy (i.e. tape). we then show two federated data modeling techniques (a) logical horizontal partitioning (lhp) of tuples and (b) logical vertical partitioning (lvp) of columns to demonstrate our database extension capabilities. we conclude with a tpc-like performance analysis of data stored on tape and disk.  felipe cariño pekka kostamaa art kaufmann john burgess
video anywhere: a system for searching and managing distributed heterogeneous video assets  visual information, especially videos, plays an increasing role in our society for both work and entertainment as more sources become available to the user. set-top boxes are poised to give home users access to videos that come not only from tv channels and personal recordings, but also from the internet in the form of downloaded and streaming videos of various types. current approaches such as electronic program guides and video search engines search for video assets of one type or from one source. the capability to conveniently search through many types of video assets from a large number of video sources with easy-to-use user profiles cannot be found anywhere yet. videoanywhere has developed such a capability in the form of an extensible architecture as well as a specific implementation using the latest in internet programming (java, agents, xml, etc.) and applicable standards. it automatically extracts and manages an extensible set of metadata of major types of videos that can be queried using either attribute-based or keyword- based search. it also provides user profiling that can be combined with the query processing for filtering. a user-friendly interface provides management of all system functions and capabilities. videoanywhere can also be used as a video search engine for the web, and a servlet-based version has also been implemented.  amit sheth clemens bertram kshitij shah
an adaptive concurrency control algorithm (abstract)  correctness of concurrent executions of multiple database transactions is assured by concurrency control techniques. performance analyses, e.g., [agr85], show that optimistic concurrency control techniques perform more efficiently than pessimistic techniques when there is low contention for the data and low resource utilization. otherwise pessimistic techniques perform better. because the designer of a database system can rarely predict data contention and resource utilization, it is desirable that a database system adaptively select a concurrency control technique at runtime.  we present an algorithm for partitioning the collection of active database transactions into a set of clusters. the partitioning algorithm guarantees that there are no data conflicts between transactions to distinct clusters. different concurrency control techniques can be applied in distinct clusters. our algorithm uses the number of transactions in a cluster as a measure of data contention. transactions in newly formed clusters are handled by an optimistic scheduler. when the number of transactions in a cluster exceeds a certain threshold, the cluster becomes pessimistic. such a cluster's current transactions complete, and then newly entering transactions can begin, managed by a pessimistic scheduler.  we have designed data structures to support the efficient maintenance of clusters. we have also begun to develop a theory of correct cluster configurations. we are undertaking a simulation study to compare the performances of pessimistic techniques, optimistic techniques, and our adaptive approach.  james canning p. muthuvelraj john sieg
ldap directory services- just another database application? (tutorial session)  the key driving force behind general-purpose enterprise directory services is for providing a central repository for commonly and widely used information such as users, groups, network service access information and profiles, security information, etc. acceptance of the lightweight directory access protocol (ldap) as an access protocol has facilitated widespread integration of these directory services into the network infrastructure and applications.  both directory and relational databases are data repositories sharing the characteristic that they have mechanisms for dealing with schema and structure of information and are suitable for systematically organized data. this tutorial describes characteristics of directories such as schema information, query language and support, storage mechanisms required, typical requirements imposed by applications, etc. we then explain the differences between a directory and relational database, and show how the two are required to co- exist in a typical enterprise.  an essential characteristic assumed for information stored in directories is that it is relatively static and that the queries are mostly read only. we describe typical directory applications to validate this assumption and project the requirements imposed on them as these applications evolve. we then describe areas of overlap between traditional databases and directories, describe some database and directory integration solutions adopted in the market, and identify areas in which directory deployment can benefit from the experience gathered by the database community.  shridhar shukla anand deshpande
simple rational guidance for chopping up transactions  chopping transactions into pieces is good for performance but may lead to non- serializable executions. many researchers have reacted to this fact by either inventing new concurrency control mechanisms, weakening serializability, or both. we adopt a different approach.  we assume a user who  • has only the degree 2 and degree 3 consistency options offered by the vast majority of conventional database systems; and  •knows the set of transactions that may run during a certain interval (users are likely to have such knowledge for online or real-time transactional applications).  given this information, our algorithm finds the finest partitioning of a set of transactions transet with the following property; if the partitioned transactions execute serializably, then transet executes serializably. this permits users to obtain more concurrency while preserving correctness. besides obtaining more inter-transaction concurrency, chopping transactions in this way can enhance intra-transaction parallelism.  the algorithm is inexpensive, running in o(n x (e + m)) time using a naive implementation where n is the number of edges in the conflict graph among the transactions, and m is the maximum number of accesses of any transaction. this makes it feasible to add as a tuning knob to practical systems.  dennis shasha eric simon patrick valduriez
building temporal structures in a layered multimedia data model  the layered multimedia data model (lmdm) aids in the specification of multimedia compositions by dividing the problem into smaller, more manageable pieces. in this paper we describe the lower two layers of the lmdm, the data definition layer, which allows the specification of multimedia objects in a database, and the data manipulation layer, which allows the specification of temporal structures built from those objects. several examples demonstrate the advantages of the layered paradigm: simple specifications, and modular, reusable components.  g. schloss m. wynblatt
microcomputer user interface toolkits (panel session): the commercial state- of-the-art  a well-designed user interface is a very valuable asset: the best available today are based on hundreds of man-years of work combining results of research in human factors, tasteful design reviewed and modified through extensive end- user testing, and many rounds of implementation effort. as a result, the user interface "toolkit" is emerging as the hottest new software item. a toolkit can provide software developers with a programming environment in which the user interface coding is already done so that new applications programs can automatically be integrated with other workstation functions.  the panel will evaluate this new trend. tesler and macgregor, will present the designs of the leading toolkit products from apple and microsoft, respectively. reed will analyze the choices from the point of view of the third party software vendors' requirements. noting that the effort going into these products may well result in de facto standard setting, buxton will question the appropriateness of making this commitment based on microcomputer hardware.  irene greif william a. s. buxton david r. reed larry tesler scott macgregor
digital library collaborations in a world community  digital libraries and their user communities are increasingly internat ional in nature. however \- though technological progress and global education have brought american and european communities closer - cross-cultural and other crosscutting issues impede the formation of world community on larger scales. the pertinent issues include: collaboration in the presence of language and cultural barriers, international copyrights, international revenue streams, and universal access. this panel will examine notions of "community" from a variety of theoretical and practical perspectives, and discuss lessons that can be gleaned from applications of the community concept. topics are expected to include scalability, sustainability, regenerative cycles in healthy communities, and examples of digital-library efforts that have international potential or implications.  david fulker sharon dawes leonid kalinichenko tamara sumner constantino thanos alex ushakov
using goms for user interface design and evaluation: which technique?  since the seminal book, the psychology of human- computer interaction, the goms model has been one of the few widely known theoretical concepts in human- computer interaction. this concept has spawned much research to verify and extend the original work and has been used in real-world design and evaluation situations. this article synthesizes the previous work on goms to provide an integrated view of goms models and how they can be used in design. we briefly describe the major variants of goms that have matured sufficiently to be used in actual design. we then provide guidance to practitioners about which goms variant to use for different design situations. finally, we present examples of the application of goms to practical design problems and then summarize the lessons learned.  bonnie e. john david e. kieras
greenstone: a comprehensive open-source digital library software system  this paper describes the greenstone digital library software, a comprehensive, open-source system for the construction and presentation of information collections. collections built with greenstone offer effective full-text searching and metadata-based browsing facilities that are attractive and easy to use. moreover, they are easily maintainable and can be augmented and rebuilt entirely automatically. the system is extensible: software "plugins" accommodate different document and metadata types.  ian h. witten stefan j. boddie david bainbridge rodger j. mcnab
rich interaction in the digital library  effective information access involves rich interactions between users and information residing in diverse locations. users seek and retrieve information from the sources---for example, file serves, databases, and digital libraries ---and use various tools to browse, manipulate, reuse, and generally process the information. we have developed a number of techniques that support various aspects of the process of user/information interaction. these techniques can be considered attempts to increase the bandwidth and quality of the interactions between users and information in an information workspace\\---an environment designed to support information work (see figure 1).  ramana rao jan o. pedersen marti a. hearst jock d. mackinlay stuart k. card larry masinter per-kristian halvorsen george c. robertson
exploiting concurrency in a dbms implementation for production systems  an important aspect of integration of ai and dbms technology is identifying functional similarities in database processing and reasoning with rules. in this paper, we focus on applying concurrency techniques to rule- based production systems. we tailor dbms concurrent execution to a production system environment and investigate the resulting concurrent execution strategies for productions. this research is in conjunction with a novel dbms mechanism for testing if the left hand side conditions of productions are satisfied. this set-oriented mechanism uses a special data structure implemented using relational tables. to demonstrate the equivalence of a serial and a concurrent (interleaved) execution strategy, for a set of productions, we assume a locking scheme to enforce serializability and specify what locks must be obtained. we define a logical commit point for a production. after this point the execution of a production is independent of all other (executing) productions. we compare the number of possible serial and parallel execution schedules.  l. raschid t. sellis c. c. lin
the pointcast network (abstract)  pointcast inc, the inventor and leader in broadcast news via the internet and corporate intranets was founded in 1992 to deliver news as it happens from leading sources such as cnn, the new york times, wall street journal interactive edition and more, directly to a viewer's computer screen.  the pointcast network is an integrated client/server system. the system give users control of selecting kinds of information the client retrieves and, within limits, the frequency of those retrievals.  the system is divided into client and server segments, referred to as "pointcast client" and "the datacenter" respectively. pointcast client is a program that runs on the user's internet-connected computer, and performs a number of functions in addition to retrieving information from the datacenter.  the server side of the system, known as the pointcast datacenter, supports the client by providing compelling content in a timely fashion. the data center is composed of multiple sites geographically distributed all over us, each carrying a number of industrial strength web servers called "pointservers". the pointservers are highly customized and "infinitely" scalable to serve close to 200 million requests handled by the pointcast network in a day.  the pointcast network receives content from over 100 different sources via satellite links or over the internet. a cluster of servers in the data center run customized processes round the clock which assimilate data from various sources to index, format and store it in multiple content databases.  this presentation will describe the basic plumbing of the pointcast network and how some of the challenges of establishing one of the busiest data centers in the world were addressed and implemented. it will focus on following issues:  fault tolerance  load balancing  achieving scalability through pre-caching on servers  packaging information to optimize internet bandwidth usage  minimizing data latency.  satish ramakrishnan vibha dayal
hypermedia conversation recording to preserve informal artifacts in realtime collaboration  we present a hypermedia-based conversation recording method to preserve informal artifacts which are obtained in a realtime collaboration. informal artifacts are not final goals but important results such as a process of a decision, an individual opinion, a rejected idea, or a nuance. conversation in a realtime collaborative session is recorded linked with a participant's handwritten scripts so that the relevant portion of the conversation can be selectively played back in the subsequent individual session. a participant can preserve informal artifacts and structure the decision-making process by playing back the conversation after the collaboration. the important feature is that a participant can insert meaningful cues in any portion of the conversation without disturbing the current way of collaboration. through the use of a prototype, we have found the effectiveness and the further improvement of this method.  t. imai k. yamaguchi t. muranaga
state of the art issues in distributed databases (panel session): form-flow application development  the development of inexpensive, powerful, microcomputers with bit-mapped graphics displays and local area networks makes it possible to provide each person in a office with a personal computer which can communicate with other computers and shared resources (e.g. printers and data). these personal computers can be used to automate many of the office tasks which currently use paper forms, telephone communication, and filing cabinets and thereby improve office worker productivity. unfortunately, existing programming languages and application development tools are not well- matched to the full-screen interactive user interfaces and the multiuser form- flow applications that these office systems require. as a result, application programs to automate offices are complex, unreliable, expensive, and time- consuming to produce. examples of these systems are keeping track of papers submitted to a journal, bug reports sent to a software organization, and purchase orders sent to a company.  we have developed an interactive, form-flow application development system (fads) which will make it easier to build these applications. the system has built-in forms (e.g. data entry and report forms), tools for combining many forms into an application (e.g. using data entered into a data entry form as arguments to a database query that produces data for a report form), facilities to send data (i.e. forms) to another user, and triggering mechanisms to allow a user's attention to be directed to important information (e.g. that a bug fix is overdue). moreover, applications are developed interactively using the same form-based user interface as the applications being created.  l. rowe
an rtp-based synchronized hypermedia live lecture system for distance education  in this article, we have introduced a "live synchronized hypermedia live lecture (shll) system" using rtp to synchronize the live presentation of streaming video lecture, html-based lecture notes, and html page navigation events. the shll framework consists of three major modules: (1) shll recorder- for recording the temporal information of the av lecture and the html-based lecture notes navigation processes. (2) shll event server- for receiving, depositing, and multicasting shll events. (3) shll browser- for presentation of the synchronized av lecture and html- based lecture notes navigation.  to manage the synchronization presentation of different media, we have proposed an rtp-based multi-sync synchronization model, which account for the human perception factors. to evaluate the performance of the proposed shll framework and synchronization model, a realsystem-based prototype synchronized html-av distance lecture system has been implemented using java/javascript and c. the prototype system certifies the feasibility of the proposed framework for synchronized hypermedia live multicasting.  herng-yow chen yen-tsung chia gin-yi chen jen-shin hong
a system for adding content-based searching to a traditional music library catalogue server  most online music library catalogues can only be searched by textual m etadata. whilst highly effective - since the rules for maintaining consistency have been refined over many years - this does not allow searching by musical content. many music librarians are familiar with users humming their enquiries. most systems providing a query by humming interface tend to run independently of music library catalogue systems and not offer similar textual metadata searching. this demonstration shows how we can integrate these two types of system based on work conducted as part of the nsf/jisc funded omras project (http://www.omras.org).  matthew j. dovey