waashk/acm huggingface dataset:
infomaster: an information integration system  infomaster is an information integration system that provides integrated access to multiple distributed heterogeneous information sources on the internet, thus giving the illusion of a centralized, homogeneous information system. we say that infomaster creates a virtual data warehouse. the core of infomaster is a facilitator that dynamically determines an efficient way to answer the user's query using as few sources as necessary and harmonizes the heterogeneities among these sources. infomaster handles both structural and content translation to resolve differences between multiple data sources and the multiple applications for the collected data. infomaster connects to a variety of databases using wrappers, such as for z39.50, sql databases through odbc, edi transactions, and other world wide web (www) sources. there are several www user interfaces to infomaster, including forms based and textual. infomaster also includes a programmatic interface and it can download results in structured form onto a client computer. infomaster has been in production use for integrating rental housing advertisements from several newspapers (since fall 1995), and for meeting room scheduling (since winter 1996). infomaster is also being used to integrate heterogeneous electronic product catalogs.  michael r. genesereth arthur m. keller oliver m. duschka
view-based query processing for regular path queries with inverse  view-based query processing is the problem of computing the answer to a query based on a set of materialized views, rather than on the raw data in the database. the problem comes in two different forms, called query rewriting and query answering, respectively. in the first form, we are given a query and a set of view definitions, and the goal is to reformulate the query into an expression that refers only to the views. in the second form, besides the query and the view definitions, we are also given the extensions of the views and a tuple, and the goal is to check whether the knowledge on the view extensions logically implies that the tuple satisfies the query.  in this paper we address the problem of view-based query processing in the context of semistructured data, in particular for the case of regular-path queries extended with the inverse operator. several authors point out that the inverse operator is one of the fundamental extensions for making regular-path queries useful in real settings. we present a novel technique based on the use of two-way finite-state automata. our approach demonstrates the power of this kind of automata in dealing with the inverse operator, allowing us to show that both query rewriting and query answering with the inverse operator has the same computational complexity as for the case of standard regular-path queries.  diego calvanese moshe y. vardi giuseppe de giacomo maurizio lenzerini
ultra-structure: a design theory for complex systems and processes  the physicist and nobel laureate ilya prigogine states that "our understanding of nature is undergoing a radical change toward the multiple, the temporal, and the complex. curiously, the unexpected complexity found in nature has not led to a slowdown in the progress of science, but on the contrary to the emergence of new conceptual structures that now appear as essential to our understanding of the physical world" [11]. we believe the challenges posed by complex systems arise primarily from the use of conceptual structures that worked well for static systems but do not work as well for more dynamic systems. we therefore propose new conceptual structures based on a different metaphysical view of the nature of complex systems.  jeffrey g. long dorothy e. denning
data sharing in group work  data sharing is fundamental to computer- supported cooperative work: people share information through explicit communication channels and through their coordinated use of shared databases. this paper examines the data management requirements of group work applications on the basis of experience with three prototype systems and on observations from the literature. database and object management technologies that support these requirements are briefly surveyed, and unresolved issues in the particular areas of access control and concurrency control are identified for future research.  irene greif sunil sarin
database patchwork on the internet  naturally, data processing requires three kinds of resources:  the data itself,  the functionality (i.e. database operations) and  the machines on which to run the operations.  because of the internet we believe that in the long run there will be alternative providers for all of these three resources for any given application. data providers will bring more and more data and more and more different kinds of data to the net. likewise, function providers will develop new methods to process and work with the data; e.g., function providers might develop new algorithms to compress data or to produce thumbnails out of large images and try to sell these on the internet. it is also conceivable, that some people allow other people to use spare cycles of their idle machines in the internet (as in the condor system of the university of wisconsin) or that some companies (cycle providers) even specialize on selling computing time to businesses that occasionally need to carry out very complex operations for which regular hardware is not sufficient.  at the university of passau, we are currently developing a distributed database system to be used in the internet. the goal is to ultimately have a system which is able to run on any machine, manage any kind of data, import any kind of data from other systems and import any kind of database operations. the system is entirely written in java. one of the most important features of the system is that it is capable of dynamically loading (external) query operators, written in java and supplied by any function provider, and executing these query operators in concert with pre-defined and other external operators in order to evaluate a query. compared to object-relational database systems, which allow to integrate external data and functionality by the means of extensions (datablades, extenders or cartridges) or heterogeneous database systems such as garlic [ms97] or tsimmis [gmpq+97], our approach makes it possible to place external query operators anywhere in a query evaluation plan as opposed to restricting the placement of external operations to the "access level" of plans. it would, for example, be possible to make our system execute a completely new relational join method, if somebody finds a new join method which is worth-while implementing. because our system is written in java, it is highly portable and could be used by data, function and cycle providers with almost no effort. furthermore, our query engine is, of course, completely distributed providing all the required infrastructure for server-server communication, name services, etc.  reinhard braumandl alfons kemper donald kossmann
vip-mdbs: a logic multidatabase system  we present a multidatabase management system built in vienna integrated prolog (vip) for cooperative management of autonomous databases. data in different databases may differ with respect to naming, structures and value types. vip- mdbs (vip multidatabase system) allows the ability to manipulate them jointly and in a non-procedural way. its features are similar to those of the relational multidatabase language msql, but adapted to logic programming. we introduce the concept of so-called semantic relations, a concept which stems from the extension of global views by deductiveness. vip-mdbs allows for representation of intentional data and formulation of recursive multiple queries.  e. kuhn t. ludwig
storytelling with digital photographs  photographs play a central role in many types of informal storytelling. this paper describes an easy-to-use device that enables digital photos to be used in a manner similar to print photos for sharing personal stories. a portable form factor combined with a novel interface supports local sharing like a conventional photo album as well as recording of stories that can be sent to distant friends and relatives. user tests validate the design and reveal that people alternate between "photo-driven" and "story-driven" strategies when telling stories about their photos.  marko balabanovic lonny l. chu gregory j. wolff
the design, simulation, and evaluation of a menu driven user interface  as the number of system users increases, the degree of formal training of the typical user declines. techniques such as menu selection, which can best accommodate the novice user, almost necessarily must be included in a strategy for person-computer communication. yet care must be taken that the experienced or sophisticated user is not encumbered with an interface that involves frustratingly slow entry of commands or procedures. this paper details the process and techniques required to develop and test an interface that would satisfy the needs of a broad spectrum of users. two design and evaluation iterations are described.  ricky e. savage james k. habinek thomas w. barnhart
design practice and interface usability: evidence from interviews with designers  research into human-computer interaction (hci) is mainly conducted by engineering psychologists, cognitive psychologists and computer scientists. the principal consumers of applied hci research, on the other hand, are human factors practitioners and system designers and developers. the hci researcher who believes his or her findings to be of practical relevance has therefore to consider the interface between researcher and practitioner as well as that between system and user: the products of hci research must not only be relevant but also "user-friendly" to the practitioner. this problem is not merely one of communication between different professional communities, as the optimal route for the translation of research findings into terms that will be of practical use in the design process is itself a matter of considerable uncertainty and debate. thus there are many instances in the research literature where apparently contradictory recommendations can all too easily be drawn from findings based on sound but, by its very nature, limited experimentation (e.g., compare the findings of landauer et al., in press, ledgard et al., 1980, and scapin, 1981, on naming text-editing operations).  one of the prerequisites for tackling both the communication problem and the translation problem is an understanding of relevant aspects of decision-making in design which influence the usability of the end-user interface. this is so for three reasons. first, an appreciation of the nature of design practice will at least help identify those areas where research input might have the greatest impact and allow researchers to direct their efforts towards them. second, it may identify possible modifications to existing design practice which would allow research input to be used more effectively. finally, it would be somewhat surprising if current design practice were not to furnish researchers with any insights into the underlying processes of users. the experience and skills of the practitioner should be a valuable source of information for the hci researcher. for these reasons, we have been documenting some of the relationships between design practice and the usability of systems for use by non-experts. while there is considerable literature on programming behaviour (e.g. mayer, 1981), reports of design behaviour are rare, other than occasional descriptions by practitioners of the interface design of their own products (e.g., botterill, 1982; smith et al., 1982). this paper focusses on the influence of the individual designer's decision-making. evidence is taken from interviews with experienced system designers concerning design issues influencing the nature of the user interface which had arisen with systems they had recently worked on. for two of the systems usability investigations had been performed (see lewis & mack, 1982 and hammond et al., 1983).  n. hammond a. jørgensen a. maclean p. barnard j. long
atomic incremental garbage collection and recovery for a large stable heap  a stable heap is storage that is managed automatically using garbage collection, manipulated using atomic transactions, and accessed using a uniform storage model. these features enhance reliability and simplify programming by preventing errors due to explicit deallocation, by masking failures and concurrency using transactions, and by eliminating the distinction between accessing temporary storage and permanent storage. stable heap management is useful for programming languages for reliable distributed computing, programming languages with persistent storage, and object-oriented database systems.  many applications that could benefit from a stable heap (e.g., computer-aided design, computer-aided software engineering, and office information systems) require large amounts of storage, timely responses for transactions, and high availability. we present garbage collection and recovery algorithms for a stable heap implementation that meet these goals and are appropriate for stock hardware. the collector is incremental: it does not attempt to collect the whole heap at once. the collector is also atomic: it is coordinated with the recovery system to prevent problems when it moves and modifies objects. the time for recovery is independent of heap size, even if a failure occurs during garbage collection.  elliot k. kolodner william e. weihl
transformation of data traversals and operations in application programs to account for semantic changes of databases  this paper addresses the problem of application program conversion to account for changes in database semantics that result in changes in the schema and database contents. with the observation that the existing data models can be viewed as alternative ways of modeling the same database semantics, a methodology of application program analysis and conversion based on an existing-dbms-model-and schema-independent representation of both the database and programs is presented. in this methodology, the source and target databases are described in terms of the association types of a semantic association model. the structural properties, the integrity constraints, and the operational characteristics (storage operation behaviors) of the association types are more explicitly defined to reveal the semantics that is generally hidden in application programs. the explicit descriptions of the source and target databases are used as the basis for program analysis and conversion. application programs are described in terms of a small number of "access patterns" which define the data traversals and operations of the programs. in addition to the methodology, this paper (1) describes a model of a generalized application program conversion system that serves as a framework for research, (2) presents an analysis of access patterns that serve as the primitives for program description, (3) delineates some meaningful semantic changes to databases and their corresponding transformation rules for program conversion, (4) illustrates the application of these rules to two different approaches to program conversion problems, and (5) reports on the development effort undertaken at the university of florida.  stanley y. w. su herman lam der her lo
the fischlar digital video system: a digital library of broadcast tvprogrammesfischl&Âࠡcute;r is a system for recording, indexing, browsing and playback ofbroadcast tv programmes which has been operational on our university campusfor almost 18 months. in this paper we give a brief overview of how the systemoperates, how tv programmes are organised for browse/playback and a shortreport on the system usage by over 900 users in our university.a. f. smeaton n. murphy n. e. o'connor s. marlow h. lee k. mcdonald p. brownej. ye
partial collection replication versus caching for information retrieval systems  the explosion of content in distributed information retrieval (ir) systems requires new mechanisms to attain timely and accurate retrieval of unstructured text. in this paper, we compare two mechanisms to improve ir system performance: partial collection replication and caching. when queries have locality, both mechanisms return results more quickly than sending queries to the original collection(s). caches return results when queries exactly match a previous one. partial replicas are a form of caching that return results when the ir technology determines the query is a good match. caches are simpler and faster, but replicas can increase locality by detecting _similarity_ between queries that are not exactly the same. we use real traces from thomas and excite to measure query locality and similarity. with a very restrictive definition of query similarity, similarity improves query locality up to 15% over exact match. we use a validated simulator to compare their performance, and find that even if the partial replica hit rate increases only 3 to 6%, it will outperform simple caching under a variety of configurations. a combined approach will probably yield the best performance.  zhihong lu kathryn s. mckinley
the specification and enforcement of authorization constraints in workflow management systems  in recent years, workflow management systems (wfmss) have gained popularity in both research and commercial sectors. wfmss are used to coordinate and streamline business processes. very large wfmss are often used in organizations with users in the range of several thousands and process instances in the range of tens and thousands. to simplify the complexity of security administration, it is common practice in many businesses to allocate a role for each activity in the process and then assign one or more users to each role---granting an authorization to roles rather than to users. typically, security policies are expressed as constraints (or rules) on users and roles; separation of duties is a well-known constraint. unfortunately, current role-based access control models are not adequate to model such constraints. to address this issue we (1) present a language to express both static and dynamic authorization constraints as clauses in a logic program; (2) provide formal notions of constraint consistency; and (3) propose algorithms to check the consistency of constraints and assign users and roles to tasks that constitute the workflow in such a way that no constraints are violated.  elisa bertino elena ferrari vijay atluri
a configuration management approach for large workflow management systems scalability to large, heterogeneous, and distributed environments is an important requirement for workflow management systems (wfms). as a consequence, the management of the configuration of a wfms installation becomes a key issue. this paper proposes an approach for managing the configuration of wfms together with an assignment strategy for workflow instances. separating the logical issues of the workflow model from the physical configuration of a wfms is the basis of our strategy. a formalization of physical organizational requirements in a wfms configuration covering access rights, usage policies, and costs for the access to wfms servers is presented and used in the assignment strategy for workflow instances. the results of our approach fit well for many existing wfms and also for the reference architecture of the workflow management coalition. hans schuster jens neeb ralf schamburger
finding redundant paths in hypermedia  web page prerequisites can be used to constrain how a user can explore a web site. this can be used in a number of ways, but plays an especially important role in educational sites. if disjunctive and conjunctive constraints are used to describe the preferences, some pages may become redundant given the user's previous path and the user may not want to visit them. the redundancy of a page is not a local property and may depend on many preferences. this paper describes an efficient algorithm that finds these redundant pages and discusses some applications of the approach.  roland hubscher
performance evaluation of a temporal database management system  a prototype of a temporal database management system was built by extending ingres. it supports the temporal query language tquel, a superset of quel, handling four types of database static, rollback, historical and temporal. a benchmark set of queries was run to study the performance of the prototype on the four types of databases. we analyze the results of the benchmark, and identify major factors that have the greatest impact on the performance of the system. we also discuss several mechanisms to address the performance bottlenecks we encountered.  ilsoo ahn richard snodgrass
supporting distributed groups with a montage of lightweight interactions  the montage prototype provides lightweight audio-video glances among distributed collaborators and integrates other applications for coordinating future contact. we studied a distributed group across three conditions: before installing montage, with montage, and after removing montage. we collected quantitative measures of usage as well as video-tape and user perception data. we found that the group used montage glances for short, lightweight interactions that were like face-to-face conversations in many respects. yet like the phone, montage offered convenient access to other people without leaving the office. most glances revealed that the person was not available, so it was important to integrate other tools for coordinating future interaction. montage did not appear to displace the use of e-mail, voice-mail, or scheduled meetings.  john c. tang ellen a. isaacs monica rua
context-based synchronization: an approach beyond semantics for concurrency control  the expressiveness of various object-oriented languages is investigated with respect to their ability to create new objects. we focus on database method schemas (dms), a model capturing the data manipulation capabilities of a large class of deterministic methods in object-oriented databases. the results clarify the impact of various language constructs on object creation. several new constructs based on expanded notions of deep equality are introduced. in particular, we provide a tractable construct which yields a language complete with respect to object creation. the new construct is also relevant to query complexity. for example, it allows expressing in polynomial time some queries, like counting, requiring exponential space in dms alone.  man h. wong divyakant agrawal
document filtering method using non-relevant information profile  document filtering is a task to retrieve documents relevant to a user's profile from a flow of documents. generally, filtering systems calculate the similarity between the profile and each incoming document, and retrieve documents with similarity higher than a threshold. however, many systems set a relatively high threshold to reduce retrieval of non-relevant documents, which results in the ignorance of many relevant documents. in this paper, we propose the use of a non-relevant information profile to reduce the mistaken retrieval of non-relevant documents. results from experiments show that this filter has successfully rejected a sufficient number of non-relevant documents, resulting in an improvement of filtering performance.  keiichiro hoashi kazunori matsumoto naomi inoue kazuo hashimoto
natural language systems: how are they meeting human needs?  one goal of natural language research is to make systems more accessible to their users by allowing them to interact with machines in a language as close as possible to the language people use among themselves. developing systems that answer natural language questions is one way to allow users to interact easily with computers. in the following sections, i briefly describe ways in which researchers have been successful in this attempt, limitations inherent in existing natural language systems, and current efforts to bring systems closer to meeting the needs of their users. to illustrate these issues, i focus on natural language database systems as one example of question- answering systems.  kathleen r. mckeown