http://hdl.handle.net/2451/14090 Search the Channel search http://archive.nyu.edu/simple-search http://hdl.handle.net/2451/25886 Title: A Quality-Aware Optimizer for Information Extraction<br/><br/>Jain, Alpa; Ipeirotis, Panagiotis G.<br/><br/>Abstract: Large amounts of structured information is buried in unstructured text.Information extraction systems can extract structured relations from thedocuments and enable sophisticated, SQL-like queries over unstructuredtext. Information extraction systems are not perfect and their outputhas imperfect precision and recall (i.e., contains spurious tuples andmisses good tuples). Typically, an extraction system has a set ofparameters that can be used as ``knobs'' and tune the system to beeither precision- or recall-oriented. Furthermore, the choice ofdocuments processed by the extraction system also affects the quality ofthe extracted relation. So far, estimating the output quality of aninformation extraction task was an ad-hoc procedure, based mainly onheuristics. In this paper, we show how to use receiver operatingcharacteristic (ROC) curves to estimate the extraction quality in astatistically robust way and show how to use ROC analysis to select theextraction parameters in a principled manner. Furthermore, we presentanalytic models that reveal how different document retrieval strategiesaffect the quality of the extracted relation. Finally, we present ourmaximum likelihood approach for estimating---on the fly---the parametersrequired by our analytic models to predict the run time and the outputquality of each execution plan. Our experimental evaluation demonstratesthat our optimization approach predicts accurately the output qualityand selects the fastest execution plan that satisfies the output quality restrictions. http://hdl.handle.net/2451/25882 Title: Get Another Label? Improving Data Quality and Data Mining UsingMultiple, Noisy Labelers<br/><br/>Sheng, Victor; Provost, Foster; Ipeirotis, Panagiotis G.<br/><br/>Abstract: This paper addresses the repeated acquisition of labels for data itemswhen the labeling is imperfect. We examine the improvement (or lackthereof) in data quality via repeated labeling, and focus especially onthe improvement of training labels for supervised induction. With theoutsourcing of small tasks becoming easier, for example via Rent-A-Coderor Amazon's Mechanical Turk, it often is possible to obtainless-than-expert labeling at low cost. With low-cost labeling, preparingthe unlabeled part of the data can become considerably more expensivethan labeling. We present repeated-labeling strategies of increasingcomplexity, and show several main results. (i) Repeated-labeling canimprove label quality and model quality, but not always. (ii) Whenlabels are noisy, repeated labeling can be preferable to single labelingeven in the traditional setting where labels are not particularly cheap.(iii) As soon as the cost of processing the unlabeled data is not free,even the simple strategy of labeling everything multiple times can giveconsiderable advantage. (iv) Repeatedly labeling a carefully chosen setof points is generally preferable, and we present a robust techniquethat combines different notions of uncertainty to select data points forwhich quality should be improved. The bottom line: the results showclearly that when labeling is not perfect, selective acquisition ofmultiple labels is a strategy that data miners should have in theirrepertoire; for certain label-quality/cost regimes, the benefit is substantial. http://hdl.handle.net/2451/23783 Title: Does Chatter Matter? The Impact of User-Generated Content on Music Sales<br/><br/>Dhar, Vasant; Chang, Elaine<br/><br/>Abstract: The Internet has enabled the era of user-generated content, potentiallybreaking the hegemony of traditional content generators as the primarysources of &ldquo;legitimate&rdquo; information. Prime examples ofuser-generated content are blogs and social networking sites, whichallow easy publishing of and access to information. In this study, weexamine the usefulness of such content, consisting of data from blogsand social networking sites in predicting sales in the music industry.We track the changes in online chatter for a sample of 108 albums forfour weeks before and after their release dates. We use linear andnonlinear regression to identify the relative significance of onlinevariables on their observation date in predicting future album unitsales two weeks ahead Our findings are as follows: (a) the volume ofblog posts about an album is positively correlated with future sales,(b) greater increases in an artist&rsquo;s Myspace friends week overweek have a weaker correlation to higher future sales, (c) traditionalfactors are still relevant &ndash; albums released by major labels andalbums with a number of reviews from mainstream sources like RollingStone also tended to have higher future sales. More generally, the studyprovides some preliminary answers for marketing managers interested inassessing the relative importance of the burgeoning number of &ldquo;Web2.0&rdquo; information metrics that are becoming available on theInternet, and how looking at interactions among them could providepredictive value beyond viewing them in isolation. The study alsoprovides a framework for thinking about when user-generated contentinfluences decision making. http://hdl.handle.net/2451/23604 Title: Deriving the Pricing Power of Product Features by Mining Consumer Reviews<br/><br/>Archak, Nikolay; Ghose, Anindya; Ipeirotis, Panagiotis G.<br/><br/>Abstract: The growing pervasiveness of the Internet has changed the way thatconsumers shop for goods. Increasingly, user-generated product reviewsserve as a valuable source of information for customers making productchoices online. While there is a significant body of theory onmulti-attribute choice under uncertainty, the literature that examinesproduct reviews has not built on this stream of theory for a variety ofreasons. Typically, the impact of product reviews has been incorporatedby numeric variables representing the valence and volume of reviews. Inthis paper we posit that the information embedded in product reviewscannot be captured by a single scalar value. Rather, we argue thatproduct reviews are multifaceted and hence, the textual content ofproduct reviews is an important determinant of consumers' choices, overand above the valence and volume of reviews. We provide a text miningtechnique that allows us to incorporate text in choice and panel datamodels by decomposing textual reviews into segments, evaluatingdifferent product features. We test our approach on a unique datasetcollected from Amazon, and demonstrate how it can be used to learnconsumers' relative preferences for different product features. Thedataset used contains three different groups of products (digitalcameras, camcorders, PDAs), associated sales data and consumer reviewdata gathered over a 15-month period. Additionally, we present anddiscuss two experimental techniques that can be used to alleviate theproblem of data sparsity and of omitted variables: the first techniquemodels consumer opinions as elements of a tensor product of independentfeature and evaluation spaces and the second technique clusters rareopinions based on pointwise mutual information. The paper concludes bydiscussing the managerial relevance of this work as a tool forextracting actionable business intelligence from user-generated content. http://hdl.handle.net/2451/23407 Title: Social Network Collaborative Filtering<br/><br/>Zheng, Rong; Provost, Foster; Ghose, Anindya<br/><br/>Abstract: This paper reports on a preliminary empirical study comparing methodsfor collaborative filtering (CF) using explicit data on consumers&rsquo;social networks. To our knowledge it is the first study to carefullyevaluate the potential of explicit, publicly represented social networksfor making product recommendations. Understanding social-network CF isimportant because traditional CF over a large consumer base istremendously expensive computationally. An often-ignored aspect of CF isthe selection of the set of users from which to make recommendations.Social theory tells us that social relationships are likely to connectsimilar people. If this similarity is in line with the recommendationtask, they may provide a small, dense set of &ldquo;recommenders&rdquo;for CF. We examine a unique dataset from Amazon.com that contains asocial network of consumer-selected friends. We examine two ways toincorporate social-network information into CF: using the social networkto restrict the set of recommenders selected, and (further) usingproximity in the social network to modify the traditional CFcalculation. The results show that that CF with social-network membersselected as recommenders can be remarkably superior as compared tocollaborative filtering with the recommenders not socially connected.Once the social network is selected, social network proximity does notseem to improve recommendations. http://hdl.handle.net/2451/23402 Title: Leveraging Aggregate Ratings for Better Recommendations<br/><br/>Umyarov, Akhmed; Tuzhilin, Alexander<br/><br/>Abstract: The paper presents a method that uses aggregate ratings provided byvarious segments of users for various categories of items to derivebetter estimations of unknown individual ratings. This is achieved byconverting the aggregate ratings into constraints on the parameters of arating estimation model presented in the paper. The paper alsodemonstrates theoretically that these additional constraints reducerating estimation errors resulting in better rating predictions. http://hdl.handle.net/2451/15026 Title: Collective Inference for Consumer Networks<br/><br/>Hill, Shawndra; Provost, Foster; Volinsky, Chris http://hdl.handle.net/2451/14872 Title: Geography and Electronic Commerce: Measuring Convenience, Selection, and Price<br/><br/>Forman, Chris; Ghose, Anindya; Goldfarb, Avi<br/><br/>Abstract: We develop a formal model of online-offline substitution to identifythree factors that drive consumers to purchase online: convenience,selection, and price. This model builds hypotheses on how features ofoffline retail supply impact online purchasing. We then examine how thelocal availability of offline retail options drives use of the onlinechannel and consequently how the convenience, selection, and priceadvantages of the online channel may vary by geographic location. Inparticular, we examine the effect of local store openings on online bookpurchases in that location. We explore this problem using data fromAmazon on the top selling books for 1501 unique locations in the US for10 months ending in January 2006. In addition to this data, we useinformation on changes in local retail competition as measured byopenings of large specialty bookstores such as Borders or Barnes &amp;Noble and discount stores such as Wal-Mart or Target. We show that evencontrolling for product-specific preferences by location, changes inlocal retail options have substantial effects on online purchases. Wedemonstrate how the convenience, selection, and price benefits of theInternet are different for customers in different types of locations.More generally, we show that geography significantly impacts the benefitthat consumers derive from electronic markets. http://hdl.handle.net/2451/14812 Title: Towards a Query Optimizer for Text-Centric Tasks<br/><br/>Ipeirotis, Panagiotis G.; Agichtein, Eugene; Jain, Pranay; Gravano, Luis<br/><br/>Abstract: Text is ubiquitous and, not surprisingly, many important applicationsrely on textual data for a variety of tasks. As a notable example,information extraction applications derive structured relations fromunstructured text; as another example, focused crawlers explore the webto locate pages about specific topics. Execution plans for text-centrictasks follow two general paradigms for processing a text database:either we can scan, or &quot;crawl,&quot; the text database or,alternatively, we can exploit search engine indexes and retrieve thedocuments of interest via carefully crafted queries constructed intask-specific ways. The choice between crawl- and query-based executionplans can have a substantial impact on both execution time and output&quot;completeness&quot; (e.g., in terms of recall). Nevertheless, thischoice is typically ad-hoc and based on heuristics or plain intuition.In this article, we present fundamental building blocks to make thechoice of execution plans for text-centric tasks in an informed,cost-based way. Towards this goal, we show how to analyze query- andcrawl-based plans in terms of both execution time and outputcompleteness. We adapt results from random-graph theory and statisticsto develop a rigorous cost model for the execution plans. Our cost modelreflects the fact that the performance of the plans depends onfundamental task-specific properties of the underlying text databases.We identify these properties and present efficient techniques forestimating the associated parameters of the cost model. We also presenttwo optimization approaches for text-centric tasks that rely on thecost-model parameters and select efficient execution plans. Overall, ouroptimization approaches help build efficient execution plans for a task,resulting in significant efficiency and output completeness benefits. Wecomplement our results with a large-scale experimental evaluation forthree important text-centric tasks and over multiple real-life data sets. http://hdl.handle.net/2451/14811 Title: Information Disclosure and Regulatory Compliance: Economic Issues andResearch Directions<br/><br/>Ghose, Anindya<br/><br/>Abstract: The Sarbanes Oxley Act (SOA) introduced significant changes to financialpractice and corporate governance regulation, including stringent newrules designed to protect investors by improving the accuracy andreliability of corporate disclosures. Briefly speaking, it requiresmanagement to submit a report containing an assessment of theeffectiveness of the internal control structure, a description ofmaterial weaknesses in such internal controls and of any materialnoncompliance. Such mandatory regulations can have some broaderramifications on firm profitability, market structure and socialwelfare, many of which were unintended when policy makers firstformulated this Act. Moreover, the tight coupling between complianceactivities, information disclosure and IT investments can haveimplications for IT governance because of its potential to changerelationships between technology investments and business. This articleaims to provide some intuitive insights into the trade-offs involved forfirms in disclosure of such information, and gives an overview of someresearch questions that would be of interest to academics, industryexecutives and policy makers alike. http://hdl.handle.net/2451/14810 Title: A Strategic Analysis of Information Sharing Among Cyber Attackers<br/><br/>Ghose, Anindya; Hausken, Kjell<br/><br/>Abstract: One firm invests in security to defend against cyber attacks by twohackers. Each hacker chooses an optimal attack, and they shareinformation with each other about the firm's vulnerabilities. Eachhacker prefers to receive information, but delivering gives competitiveadvantage to the other hacker. We find that each hacker's attack andinformation sharing are strategic complements while one hacker's attackand the other hacker's information sharing are strategic substitutes.The attack is inverse U-shaped in the firm's unit defense cost, andreaches zero, while the firm's defense and profit decrease, and thehackers' information sharing and profit increase. The firm's profitincreases in the hackers' unit cost of attack, while the hackers'information sharing and profit decrease. Our analysis also reveals theinteresting result that the cumulative attack level of the hackers isnot affected by the effectiveness of information sharing between themand moreover, is also unaffected by the intensity of joint informationsharing. We also find that as the effectiveness of information sharingbetween hackers increases relative to the investment in attack, thefirm's investment in cyber security defense and profit are constant, thehackers' investments in attacks decrease, and information sharing levelsand hacker profits increase. In contrast, as the intensity of jointinformation sharing increases, while the firm's investment in cybersecurity defense and profit remain constant, the hackers' investments inattacks increase, and the hackers' information sharing levels andprofits decrease. Increasing the firm's asset causes all the variablesto increase linearly, except information sharing which is constant. Weextend our analysis to endogenize the firm's asset and this analysislargely confirms the preceding analysis with a fixed asset. http://hdl.handle.net/2451/14809 Title: A Multi-Level Examination of the Impact of Social Identities on EconomicTransactions in Electronic Markets<br/><br/>Forman, Chris; Ghose, Anindya; Wiesenfeld, Batia<br/><br/>Abstract: Three of the most important uses of the Internet today are as aneconomic marketplace, as a forum for social interaction, and as a sourceof information. In this paper, we explore how these three activitiescome together, in the form of emergent social communities built aroundinformation exchanges within IT-enabled electronic marketplaces. Drawingon social identity theory, we suggest that the relationship betweenonline consumer reviews and internet product sales is partiallyexplained by social identity processes. Using a unique dataset based onboth chronologically compiled ratings as well as reviewercharacteristics for a given set of products and geographicallocation-based purchasing behavior from Amazon, we provide evidence atthe community level linking the prevalence of identity claiming behaviorin an online community with subsequent product sales. In addition, weshow that when reviewers claim to be from a particular geographiclocation, subsequent product sales are higher in that region. At thereview level of analysis, we show that subsequent reviews conform toidentity-claiming norms set in previous reviews, and that identityclaiming that conforms to community norms elicits identity granting.Furthermore, our results suggest that the prevalence of identitygranting has implications for economic exchange in the form of productsales. Implications for research on word-of-mouth and electroniccommunities are discussed. http://hdl.handle.net/2451/14808 Title: Does IT Matter in Business Education? Interviews with Business School Deans<br/><br/>Dhar, Vasant; Sundararajan, Arun<br/><br/>Abstract: How are business schools thinking about developing leaders for theemerging digital economy? To answer this question, we interviewed 45business school deans about whether knowledge about IT in businessshould be a part of core MBA education, and if so, how this knowledgeshould be delivered. A majority of deans recognize the importance of ITin business and the need for its presence in a forward looking corebusiness curriculum that is training managers for an increasingly globaland information rich future. There are three themes around which such apresence is described by them: understanding how the transformative andwealth generating potential of IT changes business and society,understanding how to make successful IT investment decisions, andfacilitating innovation and creativity in the use of increasinglyavailable data for decision making. However, a significant fraction ofthese deans struggle with the delivery of IT content in their corecurriculum, and there is a clear divergence between the extent to whichbusiness school leadership considers IT in business important, and itsrealized presence in core MBA education. We identify the main reasonsthat contribute towards this divergence and how some schools areaddressing it. Based on our findings, we outline the business importanceand intellectual foundations for a natural question around which coreeducation about IT in business can be structured, which asks &quot;Howdoes IT transform business and society?&quot; http://hdl.handle.net/2451/14803 Title: Implementing Packaged Software<br/><br/>Lucas, Henry C., Jr.; Walton, Eric J.; Ginzberg, Michael J.<br/><br/>Abstract: This article presents a model of the implementation process fordedicated packages and describes a research project to test the modelundertaken with the cooperation of a major computer vendor. Data werecollected from 78 individuals in 18 firms using the package and from thepackage vendor. The results of the study offer some support for themodel, along with suggestions for package implementation for both thecustomer and package vendor. http://hdl.handle.net/2451/14802 Title: IMPACT OF OFFICE AUTOMATION ON SOCIETY: Implications for Education,Policy and Research<br/><br/>Olson, Margrethe H.; White, Norman H. http://hdl.handle.net/2451/14801 Title: Modeling and Managing Changes in Text Databases<br/><br/>Ipeirotis, Panagiotis G.; Ntoulas, Alexandros; Cho, Junghoo; Gravano, Luis<br/><br/>Abstract: Large amounts of (often valuable) information are stored inweb-accessible text databases. ``Metasearchers'' provide unifiedinterfaces to query multiple such databases at once. For efficiency,metasearchers rely on succinct statistical summaries of the databasecontents to select the best databases for each query. So far, databaseselection research has largely assumed that databases are static, so theassociated statistical summaries do not need to change over time.However, databases are rarely static and the statistical summaries thatdescribe their contents need to be updated periodically to reflectcontent changes. In this article, we first report the results of astudy showing how the content summaries of 152 real web databasesevolved over a period of 52 weeks. Then, we show how to use ``survivalanalysis'' techniques in general, and Cox's proportional hazardsregression in particular, to model database changes over time andpredict when we should update each content summary. Finally, we exploitour change model to devise update schedules that keep the summaries upto date by contacting databases only when needed, and then we evaluatethe quality of our schedules experimentally over real web databases. http://hdl.handle.net/2451/14769 Title: A Bootstrap Evaluation of the Effect of Data Splitting on Financial Time Series<br/><br/>LeBaron, Blake; Weigend, Andreas S.<br/><br/>Abstract: This article exposes problems of the commonly used technique ofsplitting the available data into training, validation, and test setsthat are held fixed, warns about drawing too strong conclusions fromsuch static splits, and shows potential pitfalls of ignoring variabilityacross splits. Using a bootstrap or resampling method, we compare theuncertainty in the solution stemming from the data splitting with neuralnetwork specific uncertainties (parameter initialization, choice ofnumber of hidden units, etc.). We present two results on data from theNew York Stock Exchange. First, the variation due to differentresamplings is significantly larger than the variation due to differentnetwork conditions. This result implies that it is important to notover-interpret a model (or an ensemble of models) estimated on onespecific split of the data. Second, on each split, the neural networksolution with early stopping is very close to a linear model; nosignificant nonlinearities are extracted. http://hdl.handle.net/2451/14768 Title: Bounded Rationality, Indeterminacy, and the Theory of the Firm<br/><br/>Radner, Roy http://hdl.handle.net/2451/14767 Title: Profit Maximization and the Market Selection Hypothesis<br/><br/>Dutta, Prajit K.; Radner, Roy<br/><br/>Abstract: We examine the proposition chat competitive firms must behave as if theywere maximizing profits; otherwise they would go bankrupt, or even failto be financed in a competitive capital market. We investigate a modelin which an entrepreneur raises funds for a risky enterprise on acompetitive capital market, by offering a &quot;dividend policy&quot;based on the realized (stochastic) flow of earnings. We show that anentrepreneur who maximizes the expected sum of discounted dividends issure to fal1 in finite time. On the other hand, many other behavioursyield positive expected profits and are able to attract investmentfunds, and yet result in a positive probability of surviving forever. Asa consequence, if new firms have sufficiently diverse behaviours, theneven if there is a constant stream of new entrants, after a long timepractically all of the surviving firms will not have been maximizing profit. http://hdl.handle.net/2451/14766 Title: Information Technology, Competition and Market Transformations:Re-engineering the Dutch Flower Auctions<br/><br/>Kambil, Ajit; van Heck, Eric<br/><br/>Abstract: The Dutch flower auctions have played a critical role in the worldcut-flower industry by providing efficient centers for pricedetermination and transactions of flowers between buyers and sellers.These auctions owned by Dutch cut-flower grower cooperatives havetraditionally used the &Atilde;&cent;&Acirc;€&Acirc;œDutchauction&Atilde;&cent;&Acirc;€&Acirc; as the mechanism for pricedetermination. This paper considers how changing patters ofinternational competition, buyer preferences and information technologyare likely to effect the organization of the Dutch flower auction. Weprovide a framework for analyzing the merits of different transactionmodels and use this framework to evaluate the strengths and weaknessesof existing and proposed electronic auction models for trading flowers.We propose information technology will enable new forms of trading thatwill partly replace and supplement the traditional Dutch auction as amethod of organizing price determination and transactions. We identifyhow electronic trading will differ from prior mechanisms, and considerkey challenges to the implementation of new auction models.Specifically we illustrate how the current auctions have been structuredto serve the interests of growers, while electronic markets willprimarily benefit buyers. Thus we highlight the importance of alteringincentive and ownership structures in the Dutch flower industry toeffectively transition to new electronic markets. This case illustratesthe various complex issues that arise in the design and implementationof electronic markets, in settings characterized by changingtechnologies, pre-existing organizational processes and power structures. http://hdl.handle.net/2451/14765 Title: Templar: A Knowledge-Based Language for Software Specifications UsingTemporal Logic<br/><br/>Tuzhilin, Alexander<br/><br/>Abstract: A software specification language Templar is defined in this article.The development of the language was guided by the following objectives:requirements specifications written in Templar should have a clearsyntax and formal semantics, should be easy for a systems analyst todevelop and for an end-user to understand, and it should be easy to mapthem into a broad range of design specifications. Templar is based ontemporal logic and on the Activity-Event-Condition- Activity model of arule which is an extension of the Event-Condition-Activity model inactive databases. The language supports a rich set of modelingprimitives, including rules, procedures, temporal logic operators,events, activities, hierarchical decomposition of activities,parallelism, and decisions combined together into a cohesive system. http://hdl.handle.net/2451/14764 Title: On integrating hypermedia into decision support and other information systems<br/><br/>Bieber, Michael<br/><br/>Abstract: The goal of this research is to provide hypermedia functionality to allinformation systems that interact with people. Hypermedia is a conceptinvolving access to information, embodying the notions ofcontext-sensitive navigation, annotation and tailored presentation. Thispaper presents the architecture of a system-level hypermedia engine,designed both to manage full hypermedia functionality for an informationsystem and to bind interface-oriented front-end systems with separatecomputation-oriented back-end systems. The engine dynamicallysuperimposes a hypermedia representation over a back-end application'sknowledge components and processes. The hypermedia engine generates thisrepresentation using bridge laws, which capture the internal structureof client systems. Users access the application through its hypermediarepresentation. The paper also describes a set of minimal requirementsfor integrating the hypermedia engine with an information system. Theseguidelines apply to all integration efforts, not just that describedhere. Information systems will require some supplementary routines forthe engine to manage hypermedia functionality for them. The moresophisticated and cooperative the information system, the higher thelevel of hypermedia support the engine will provide. http://hdl.handle.net/2451/14763 Title: A Data Base for Operations Research Models<br/><br/>Stohr, Edward A.; Tanniru, Mohan R.<br/><br/>Abstract: This paper develops the design of a data base system to supportoperations research models in the context of an integrated planningsystem involving a number of different users and computer programs. Therequirements for such a system are described, a&Atilde;&cent;&Acirc;€&Acirc;œnetwork&Atilde;&cent;&Acirc;€&Acirc; database schema is developed and the schema and command language areillustrated through a specific example. http://hdl.handle.net/2451/14762 Title: The Impact of Office Automation on the Organization: Some Implicationsfor Research and Practice<br/><br/>Olson, Margrethe H.; Lucas, Henry C., Jr.<br/><br/>Abstract: Computer technology has recently been applied to the automation ofoffice tasks and procedures. Much of the technology is aimed not atimproving the efficiency of current office procedures, but at alteringthe nature of office work altogether. The development of automatedoffice systems raises a number of issues for the organization. How willthis technology be received by organization members? How will it affectthe definition of traditional office work? What will be its impact onindividuals, work groups, and the structure of the organization? Thispaper presents a descriptive model and propositions concerning thepotential impacts of office automation on the organization and itstresses the need, when implementing automated office systems, to take abroad perspective of their potential positive and negative effects onthe organization. The need for further research examining the potentialeffects of office automation is emphasized. http://hdl.handle.net/2451/14761 Title: Personalized Pricing and Quality Design<br/><br/>Ghose, Anindya; Huang, Ke-Wei<br/><br/>Abstract: We develop an analytical framework to investigate the competitiveimplications of personalized pricing and quality allocation (PPQ),whereby firms charge different prices and offer different qualities todifferent consumers, based on their willingness to pay. We embed PPQ ina model of spatial differentiation, and show how information aboutconsumer preferences affects multi-productfirms&Atilde;ƒ&Acirc;ƒ&Atilde;‚&Acirc;&cent;&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;€&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;™choices over pricing schedules and product line offerings. We show thatfirms&Atilde;ƒ&Acirc;ƒ&Atilde;‚&Acirc;&cent;&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;€&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;™optimal pricing strategies with PPQ will be non-monotonic in consumervaluations. Our model sheds light on the different product qualityschedules offered by firms, given that one or both firms implement PPQ.Contrary to prior literature on one-to-one marketing, we show that evensymmetric firms can avoid the well-knownPrisoner&Atilde;ƒ&Acirc;ƒ&Atilde;‚&Acirc;&cent;&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;€&Atilde;ƒ&Acirc;‚&Atilde;‚&Acirc;™sDilemma problem due to the quality enhancement effect at the individualconsumer level. The rent extraction effect due to quality enhancementdominates the adverse effect of price competition. Moreover, this resultis stronger when firms have a larger proportion of loyal consumers. Whenboth firms have PPQ, consumer surplus is non-monotonic in valuationssuch that some low valuation consumers get higher surplus than highvaluation consumers. For a wide range of fixed costs, we alsodemonstrate some results on the profitability of adopting PPQ and showthe emergence of asymmetric equilibria, where one firm adopts PPQ andthe other firm does not when the number of loyal customers is less thana critical value. We extend our analysis to asymmetric firms and showthat when one firm adopts PPQ, it always increases its quality levelwhile the other firm keeps its quality schedule unchanged compared towhen neither firm has PPQ. We demonstrate that a firm with an ex-ante,smaller loyal segment can be better off with PPQ. http://hdl.handle.net/2451/14760 Title: Duplicate Record Detection: A Survey<br/><br/>Elmagarmid, Ahmed; Ipeirotis, Panagiotis G.; Verykios, Vassilios<br/><br/>Abstract: Often, in the real world, entities have two or more representations indatabases. Duplicate records do not share a common key and/or theycontain errors that make duplicate matching a difficult task. Errors areintroduced as the result of transcription errors, incompleteinformation, lack of standard formats or any combination of thesefactors. In this article, we present a thorough analysis of theliterature on duplicate record detection. We cover similarity metricsthat are commonly used to detect similar field entries, and we presentan extensive set of duplicate detection algorithms that can detectapproximately duplicate records in a database. We also cover multipletechniques for improving the efficiency and scalability of approximateduplicate detection algorithms. We conclude with a coverage of existingtools and with a brief discussion of the big open problems in the area. http://hdl.handle.net/2451/14759 Title: Classification-Aware Hidden-Web Text Database Selection<br/><br/>Ipeirotis, Panagiotis G.; Gravano, Luis<br/><br/>Abstract: Many valuable text databases on the web have non-crawlable contents thatare ``hidden'' behind search interfaces. Metasearchers are helpful toolsfor searching over multiple such ``hidden-web'' text databases at oncethrough a unified query interface. An important step in themetasearching process is database selection, or determining whichdatabases are the most relevant for a given user query. Thestate-of-the-art database selection techniques rely on statisticalsummaries of the database contents, generally including the databasevocabulary and the associated word frequencies. Unfortunately,hidden-web text databases typically do not export such summaries, soprevious research has developed algorithms for constructing approximatecontent summaries from document samples extracted from the databases viaquerying. We present a novel ``focused probing'' sampling algorithm thatdetects the topics covered in a database and adaptively extractsdocuments that are representative of the topic coverage of the database.Our algorithm is the first that constructs content summaries thatinclude the frequencies of the words in the database. Unfortunately,Zipf's law practically guarantees that, for any relatively largedatabase, content summaries built from moderately sized document sampleswill fail to cover many low-frequency words; in turn, incomplete contentsummaries might negatively affect the database selection process,especially for short queries with infrequent words. To enhance thesparse document samples and improve the database selection decisions, weexploit the fact that topically similar databases tend to have similarvocabularies, so samples extracted from databases with a similar topicalfocus can complement each other. We have developed two databaseselection algorithms that exploit this observation. The first algorithmproceeds hierarchically and selects the best category for a query, andthen sends the query to the appropriate databases in the chosencategory. The second algorithm uses ``shrinkage,'' a statisticaltechnique for improving parameter estimation in the face of sparse data,to enhance the database content summaries with category-specific words.We describe how to modify existing database selection algorithms toadaptively decide --at run-time-- whether shrinkage is beneficial for aquery. A thorough evaluation over a variety of databases, including 315real web databases as well as TREC data, suggests that the proposedsampling methods generate high-quality content summaries and thedatabase selection algorithms produce significantly more relevantdatabase selection decisions and overall search results than existing algorithms. http://hdl.handle.net/2451/14758 Title: Dynamic Pricing of Network Goods with Boundedly Rational Consumers<br/><br/>Radner, Roy; Sundararajan, Arun<br/><br/>Abstract: We present a model of dynamic monopoly pricing for a good that displaysnetwork effects. In contrast with the standard notion of arational-expectations equilibrium, we model consumers as boundedlyrational, and unable either to pay immediate attention to each pricechange, or to make accurate forecasts of the adoption of the networkgood. Our analysis shows that the seller&Atilde;&cent;&Acirc;€&Acirc;™soptimal price trajectory has the following simple structure: the priceis zero when the product user base is below a specific threshold, and ischosen to keep user base stationary once this threshold demand level hasbeen attained. We show that our prescribed pricing policy is robust to anumber of extensions, which include theproduct&Atilde;&cent;&Acirc;€&Acirc;™s user base evolving over time, afraction of consumers being sufficiently rational to make accurateadoption forecasts, and consumers basing their choices on a mixture of amyopic and a &quot;stubborn&quot; expectation of adoption. Our resultsdiffer significantly from those that would be predicted by a model basedon rational-expectations equilibrium, and are more consistent with thepricing of network goods observed in practice. http://hdl.handle.net/2451/14757 Title: The Dimensions of Reputation in Electronic Markets<br/><br/>Ghose, Anindya; Ipeirotis, Panagiotis G.; Sundararajan, Arun<br/><br/>Abstract: We present a framework for identifying the different dimensions ofonline reputation and characterizing their influence on the pricingpower of sellers. Our theory predicts that sellers with better recordedonline reputation can successfully charge higher prices than competingsellers of identical products, and that their pricing power increaseswith their recorded level of experience. We develop and implement a newtext mining technique that identities and quantitatively assessesdimensions of importance in reputation profiles, and use this techniqueto create a new data set containing detailed reputation profiles andprices for sellers in over 9,500 transactions for consumer software onAmazon.com's online secondary marketplace. The estimation of a set ofeconometric models on this data set validates the predictions of ourtheory, and further, ranks these dimensions of reputation based on theireffect on measured seller value, identifying those that have the mostsignificant impact on reputation. This paper is the first study thatintegrates econometric and text mining techniques toward a more completeanalysis of the information captured by reputation systems, and itpresents new evidence of the importance of their effective and judicious design. http://hdl.handle.net/2451/14749 Title: Are Digital Rights Valuable? Theory and Evidence from eBook Pricing<br/><br/>Oestreicher-Singer, Gal; Sundararajan, Arun<br/><br/>Abstract: The effective management of digital rights is the central challenge inmany industries making the transition from physical to digital products.We present a new model that characterizes the value of these digitalrights when products are sold both embedded in tangible physicalartifacts, and as pure digital goods, and when granting rights permittedby one&acirc;€™s digital rights management (DRM) platform may affect theextent of digital piracy. Our model indicates that in the absence ofpiracy, digital rights should be unrestricted, since a seller can useits pricing strategy to optimally balance sales between physical anddigital goods. However, the threat of piracy limits the extent to whichdigital rights should be granted: the value of digital rights isdetermined not only by their direct effect on the quality of legaldigital goods, but by a differential piracy effect that can lower aseller&acirc;€™s pricing power. When the latter effect is sufficientlyhigh, granting digital rights can have a detrimental effect on value&acirc;€” our model indicates that this kind of effect is more likely tobe observed for digital rights that aim to replicate the consumptionexperience of physical goods, rather than enhancing a customer&acirc;€™sdigital experience. We test the predictions of our analytical modelusing data from the ebook industry. Our empirical evidence supports ourtheoretical results, showing that four separate digital rights each havean economically significant impact on ebook prices, and establishingthat the digital rights which aim to replicate physical consumptionwhile increasing the threat of piracy are the ones that have negativeimpact on seller value. We also show that if the pricing of a digitalgood is keyed off that of an existing tangible good, optimal pricingchanges for the former should be more nuanced, rather than simplymirroring changes in the price of the latter, and we discuss the effectof the technological sophistication of potential customers on optimalpricing and rights management. Our results represent new evidence of theimportance of an informed and judicious choice of the different digitalrights granted by a DRM platform, and provide a new framework forguiding managers in industries that are progressively being digitized. http://hdl.handle.net/2451/14748 Title: Pricing Models for On-Demand Computing<br/><br/>Huang, Ke-Wei; Sundararajan, Arun<br/><br/>Abstract: On-demand computing provides a new way for companies to manage and usetheir IT infrastructure. This model of corporate computing radicallychanges the way companies pay for their IT infrastructure, basing it on&quot;pay per use&quot; rather than on the fixed infrastructureinvestments such companies are accustomed to. A clear theoreticalunderstanding of pricing on-demand computing is thus central to theviability and growth of this nascent industry. We contribute towardssuch an understanding in this paper by modeling the optimal pricing ofon-demand computing while taking four critical factors into account: thecosts of deploying IT in-house, the business value of this IT, the scaleof the provider&acirc;€™s on-demand computing infrastructure, and thevariable costs of providing on-demand computing. Three distinct pricingmodels emerge as optimal among all possible pricing functions foron-demand computing. These models describe when volume discounting, freeusage and demand caps should be used to manage demand appropriately andprofitably. We also outline a likely path that the transformationtowards on-demand computing will follow &acirc;€” under which low-usagecustomers are targeted initially, followed by a broadening of themarket, and finally, a focus on profiting from inducing adoption byhigh-usage customers &acirc;€” and prescribe how the associated pricingmodels should evolve appropriately. http://hdl.handle.net/2451/14629 Title: Technology Acceptance and Performance: A Field Study of Broker Workstations<br/><br/>Lucas, Henry C., Jr.; Spitler, Valerie<br/><br/>Abstract: We develop a model to predict 1) the use of a multifunctional, brokerworkstation with a windowed interface and 2) the relationship betweenworkstation use and performance. Brokers and sales assistants in theprivate client group of a major investment bank use this workstation asan integral part of their jobs. Our model explains some of the variancein their usage, intended usage and performance, but the variables thatare most salient in the model differ between brokers and salesassistants. There is evidence that low performing brokers use theworkstation more than higher performing brokers; the results alsosuggest that a different type of training may be needed forsophisticated workstations for professionals than for clerical personnellearning to use transactions processing systems. We believe it isimportant to understand the acceptance of technology and therelationship between system use and performance if firms are to obtain areturn from investing in information technology. http://hdl.handle.net/2451/14628 Title: THE PRESIDENT AND INFORMATION MANAGEMENT: AN EXPERIMENT IN THE CARTERWHITE HOUSE<br/><br/>Turner, Jon A.; Gosden, John A. http://hdl.handle.net/2451/14627 Title: TOP MANAGEMENT PROBLEM SOLVING AND INFORMATION SYSTEMS<br/><br/>Lucas, Henry C., Jr.<br/><br/>Abstract: This paper presents the results of a exploratory study of problemsolving by top management in a sample of firms. The purpose of theresearch is to determine the nature of the information needed by topmanagement and the role of computer-based system in suppling it. Thepaper classifies problems according to their nature and explores theinformation sources used to solve the problems. It is clear thatcomputer-based information can aid in the solution of some of these topmanagement problems, but probably through unconventional systems. Theimplications of the study for systems design are discussed. http://hdl.handle.net/2451/14626 Title: THE IMPACT OF ORGANIZATIONAL CHARACTERISTICS ON MIS DESIGN AND IMPLEMENTATION<br/><br/>Ginzberg, Michael J.<br/><br/>Abstract: The appropriate design for an information system depends not only on thecharacteristics of the system users, but also on certain characteristicsof the organization, e.g., technology, structure, and environment.Implementation is likely to be most successful when there is a&acirc;€œfit&acirc;€ between the system and the organization. Thispaper describes an emerging theory of how organizational characteristicsdetermine information system requirements. http://hdl.handle.net/2451/14625 Title: AN INTRODUCTION TO DATA BASE MANAGEMENT<br/><br/>Veim, Joan C. http://hdl.handle.net/2451/14624 Title: A METHOD FOR MEASURING SOME PROPERTIES OF INFORMATION SYSTEMS<br/><br/>Turner, Jon A.<br/><br/>Abstract: An approach to measuring information systems properties is developed andtested with data from 38 systems in the same application area (mortgageloan servicing). The results provide support for the notion that generalmeasures of system properties can be made operational and that thesemeasures may be useful to other researchers. http://hdl.handle.net/2451/14623 Title: A CORPORATE STRATEGY FOR THE CONTROL OF INFORMATION PROCESSING<br/><br/>Lucas, Henry C., Jr.; Turner, Jon A. http://hdl.handle.net/2451/14622 Title: DATA MANAGEMENT SYSTEMS FOR MICRO-COMPUTERS: A SURVEY<br/><br/>Hughes, Alan J.; Lynch, Eileen M.; Stohr, Edward A. http://hdl.handle.net/2451/14621 Title: REMOTE OF'FICE WORK: CHANGING WORK PATTERNS IN SPACE AND TIME<br/><br/>Olson, Margrethe H. http://hdl.handle.net/2451/14620 Title: COMPUTER AND CLERICAL JOBS: THE MISSED OPPORTUNITY FOR WORK REDESIGN<br/><br/>Turner, Jon A. http://hdl.handle.net/2451/14619 Title: MANAGER OR TECHNICIAN? THE NATURE OF THE INFORMATION SYSTEMS MANAGER'S JOB<br/><br/>Ives, Blake; Olson, Margrethe<br/><br/>Abstract: The role of the information systems manager has evolved in twenty yearsfrom that of a technician managing a relatively unimportant servicefunction into that of a vice presidential-level, general manager whodepartment can substantially impact the entire organization. In thispaper we trace, by example, the historical evolution of the job and,through an observational study of six information systems managers,examine the position today. The analysis includes the daily activitiesof the managers, the nature of the oral contacts that constitute 76% oftheir day, and other points of particular interest. The informationsystems manager&acirc;€™s role is depicted as one of coordinator,motivator, and planner, with a cadre of experts, both internal andexternal, to provide technical information. http://hdl.handle.net/2451/14618 Title: CHARGEBACK SYSTEMS AND USER INVOLVEMENT IN INFORMATION SYSTEMS<br/><br/>Olson, Margrethe; Ives, Blake<br/><br/>Abstract: Computer chargeback systems are installed to meet various dataprocessing objectives. One objective is to increase user involvement indecisions regarding information systems development and use. Presumably,increasing user involvement will result in more effective informationsystems. In a field study we examine the relationship between variouscharacteristics of a computer chargeback system, the quality of thechargeback system's user interface, user involvement and user attitudesabout information systems services. Suggestions are given both for thepracticing information systems manager and for future informationsystems researchers. http://hdl.handle.net/2451/14617 Title: USER INVOLVEMENT IN SYSTEM DESIGN: AN EMPIRICAL TEST OF ALTERNATIVE APPROACHES<br/><br/>Olson, Margrethe; Ives, Blake<br/><br/>Abstract: 'User involvement' in the development of information systems is oftenassumed to be key to successful implementation. However, few empiricalstudies have clearly demonstrated a relationship between userinvolvement and two key indicators of system success: system usage anduser information satisfaction. The authors test the general hypothesisthat user involvement is a more complex concept than previous researchwould indicate; there are different types of involvement and differentstages in the system development life cycle in which users may becomeinvolved. In a study of 83 users and 23 information systems managers in23 companies, they found that only the activity of user sign-offs onproject phases had a significant correlation with both user informationsatisfaction and satisfaction with the information systems group. Theauthors conclude that there is a complex relationship between the typeand degree of user involvement and other organizational and individualfactors; this relationship affects both user satisfaction with and usageof the resulting systems. Some suggestions for further research takingthis complexity into account are given. http://hdl.handle.net/2451/14616 Title: DSS SUCCESS: MEASUREMENT AND FACILITATION<br/><br/>Ginzberg, Michael J.<br/><br/>Abstract: Decision Support Systems (DSS) represent an ever increasing portion ofthe investment in computer-based systems in organizations. Unlikeearlier systems which aimed to replace existing clerical processes withfaster, more efficient clerical processes, DSS attempt to extend andexpand the capabilities of organizational decision makers. Thisfundamental difference in purpose between DSS and clerical systemscauses our existing notions about system success to be inadequate. Thispaper explores the issue of DSS success, asking what it is, how it canbe measured, and what can be done to facilitate it. http://hdl.handle.net/2451/14615 Title: DSS FOR COOPERATIVE DECISION-MAKING<br/><br/>Stohr, Edward A. http://hdl.handle.net/2451/14614 Title: DBMS TRANSACTION TRANSLATION<br/><br/>Vassiliou, Yannis; Lochovsky, F.H.<br/><br/>Abstract: Data translation and transaction translation are two major problems thathave to be solved in order to achieve the coexistence of heterogeneousdistributed databases. In this paper we discuss the problem oftransaction translation. The nature of the problem is explored bydeveloping direct translations of transactions between the relationaland hierarchical and network models. Methods for mapping a hierarchicalor network schema to an equivalent relational schema are presented. Therelational operators projection, selection, join, insertion. deletionand update are translated to equivalent hierarchical and network operations. http://hdl.handle.net/2451/14613 Title: FUNCTIONAL DEPENDENCIES AND INCOMPLETE INFORMATION<br/><br/>Vassiliou, Yannis<br/><br/>Abstract: Functional dependencies play an important role in relational databasedesign. They are defined in the context of a single relation which atall times must contain tuples with non-null entries. In this paper weexamine an extension of the functional dependency interpretation tohandle null values, that is, entries in tuples that represent incompleteinformation in a relational database. A complete axiomatization ofinference rules for extended functional dependencies is also presented.Only after having such results is it possible to talk aboutdecompositions and normalization theory in a context of incompleteinformation. Finally, we show that there are several practicaladvantages in using nulls and a weaker notion of constraint satisfiability. http://hdl.handle.net/2451/14612 Title: USER INVOLVEMENT IN INFORMATION SYSTEMS: A CRITICAL REVIEW OF THEEMPIRICAL LITERATURE<br/><br/>Ives, Blake; Olson, Margrethe H.<br/><br/>Abstract: Considerable prescriptive literature exists which advocates userinvolvement in the development of information systems and suggestsalternative mechanisms by which such involvement can be increased.However, formal empirical studies investigating user involvement are fewin number, fragmented, and generally methodologically flawed.Furthermore, they do not provide the strong support for user involvementthat the prescriptive literature would lead one to expect. This papercritically examines past studies of user involvement, focusing onmethodological and measurement issues. The relationships between userinvolvement and system quality, system usage, information satisfaction,and user attitudes are considered. Suggestions for future research are discussed. http://hdl.handle.net/2451/14611 Title: USING DATA BASE MANAGEMENT SYSTEMS IN STATISTICAL DATA PROCESSING<br/><br/>Veim, Joan C.<br/><br/>Abstract: National and international statistical bureaus produce ca. 25,000 tablesfor publication each year, based on hundreds of inter-relatedobject-types with thousands of attributes. It would appear that thisenvironment should be well suited to the application of data basemanagement techniques for the administration of the data. This paperpresents a data oriented model of the statistical production processwhich is used as a basis for a review of the state of experience withinstatistical offices with commercially available data base managementsystems. We conclude with a presentation of some important datamanagement facilities which must be enhanced or developed in order tosupport statistical production processing. http://hdl.handle.net/2451/14610 Title: AN ON-LINE CONCEPT OF IMPLEMENTATION<br/><br/>Owens, Karl R.<br/><br/>Abstract: Systems supporting new products or services and driven byorganizationally dictated deadlines limit user input and planning priorto design. An on-line model of implementation is proposed calling forconstant re-evaluation and re-direction of the implementation as theseshifting projects develop. An application of the model with a 200,000line government systems is described. http://hdl.handle.net/2451/14609 Title: A MODEL FOR HISTORICAL DATABASES<br/><br/>Clifford, James<br/><br/>Abstract: It is becoming increasingly apparent that we are on the verge of severalnew technologies that will offer virtually unlimited secondary storageat affordable prices. Database applications can be expected to takeadvantage of this expanded storage capacity, and a particularlypromising area in this regard is the use of so-called&quot;non-deletion&quot; or &quot;historical&quot; databases. It istherefore appropriate to begin exploring formal models f o r thesehistorical databases -- models that are intrinsically oriented towardthe storage of data over the course of time, and that provide a formalsemantics for the interaction between time and the other stored dataitems. We present such a model, the Historical Database Model (HDBM),and define its semantics in terms of an underlying logical model. Forthis purpose we use the language IL-s and its model theory, a simplifiedversion of Richard Montague's higher-order lambda calculus withintensions. The HDBM is defined as an extension of the relationaldatabase model, incorporating a distinguished STATE attribute that&quot; time-stamps&quot; the facts recorded in the database. Intuitivelysuch a database can be viewed as a set of three-dimensional relations inthe ordinary sense. The formal semantics is defined in terms of objects(the values of keys), which are identified with non-varying or constantentities, and the properties of these objects (the values of non-keyattributes), which are identified with individual concepts is theintensional model. Two possible encodings of the database into thelogical model are presented and discussed. It is a widely accepted viewthat first-order logic provides a formalization of the semantics of therelational database model that has helped to clarify many of the issuesin relational database theory. We argue that the richer logic IL-s, withits built-in notion of &quot;denotation with respect to a moment oftime&acirc;€ and with its capability for naming higher-order objects,is an appropriate vehicle for providing an analogous formal theory ofthe semantics of an HDB. Finally, we briefly discuss our work usingIL-s as a target language for interpreting a natural-language queryfragment which we have defined as a Montague Grammar, and point to someinteresting topics for further research in the general area of time and databases. http://hdl.handle.net/2451/14608 Title: CONDITIONAL STATEMENTS AND PROGRAM CODING: AN EXPERIMENTAL EVALUATION<br/><br/>Vessey, Iris; Weber, Ron http://hdl.handle.net/2451/14607 Title: A SURVEY OF QUERY OPTIMIZATION IN CENTRALIZED DATABASE SYSTEMS<br/><br/>Jarke, Matthias; Koch, Juergen<br/><br/>Abstract: Efficient ways to process unanticipated queries are a crucialprerequisite for the success of generalized database management systems.A wide variety of approaches for improving the performance of queryevaluation algorithms have been proposed: logic-based and semantictransformations, fast implementations of basic operations, andcombinatorial or heuristic algorithms for generating and choosing amongalternative access plans. This paper surveys these approaches in theframework of a general query evaluation procedure using the relationalcalculus representation of queries. The focus is on centralized databasesystems; some relationships to other system types are studied. http://hdl.handle.net/2451/14606 Title: LANGUAGES FOR DECISION SUPPORT SYSTEMS: AN OVERVIEW<br/><br/>Stohr, Edward A.; White, Norman H.<br/><br/>Abstract: In this paper we survey some issues relating to the language interfacesprovided by DSS. We do this from the point-of-view of the designer ofgeneralized software for building DSS. We first describe a fairlygeneral architecture for such software. This is followed by a briefexamination of the language interface components. We list the functionsthat must be provided through the language facilities of a DSS togetherwith a number of implementation issues such as User-friendliness, degreeof procedurality and interpretation versus compilation. This provides auseful framework for the comparative evaluation of DSS packages. Finallywe discuss some possible directions for future development includingspecialized formal languages and the potential of English-like'semi-natural' languages. http://hdl.handle.net/2451/14605 Title: USER INTERFACES FOR DECISION SUPPORT SYSTEMS: AN OVERVIEW<br/><br/>Stohr, Edward A.; White, Norman H. http://hdl.handle.net/2451/14604 Title: OBSERVATIONS ON THE USE OF BEHAVIORAL MODELS IN INFORMATION SYSTEMSRESEARCH AND PRACTICE<br/><br/>Turner, Jon A.<br/><br/>Abstract: Much of the gap between the potential of Information Systems and theirrealization can be explained by behavioral and organizational issues.This paper outlines the scope of behavioral research in informationsystems using selected examples, identifies several principlesunderlying this work, and suggests reasons why the results of thisresearch are of value. http://hdl.handle.net/2451/14603 Title: A FRAMEWORK FOR THE EVALUATION OF HOSPITAL INFECTION CONTROL TECHNIQUES<br/><br/>Jarke, Matthias<br/><br/>Abstract: A cost-effectiveness method for evaluating measures againsthospital-aquired infections is based on a network interdiction model.Algorithms for optimal interdiction of the infection network arepresented and their applicability is discussed. Implications of theapproach for classifying measures, allocating costs and benefits, andanalyzing the costs of infections are described. The method is beingapplied in an interdisciplinary study conducted in several West German hospitals. http://hdl.handle.net/2451/14602 Title: DEVELOPING DECISION SUPPORT SYSTEMS: A CONTAINER MANAGEMENT EXAMPLE<br/><br/>Jarke, Matthias<br/><br/>Abstract: The problem of managing an intercontinental container transportationsystem is used as an example of how knowledge from the areas of databasedesign, management science, and human factors research can be combinedin the design of a decision support system. Using a new representationof time-related database objects, we first present a logical data modelof a container transportation system. A hierarchically distributeddecision support system can be based on this model. A physical databasestructure is proposed and a survey of partial optimization models to beused in the decision support system is given. http://hdl.handle.net/2451/14601 Title: USING RESTRICTED NATURAL LANGUAGE FOR DATA RETRIEVAL: A PLAN FOR FIELD EVALUATION<br/><br/>Turner, Jon A.; Jarke, Matthias; Stohr, Edward A.; Vassiliou, Yannis; White, Norman<br/><br/>Abstract: One strategy that has been proposed for dealing with the growing backlogfor development of applications is to give casual users languages forinteracting directly with databases. Yet, there is little agreement onthe form such languages should take. Should they be natural-like,conforming closely to a user's native tongue or should they bestructured to take advantage of the characteristics of formal languages?This paper presents the rationale for and design of a field evaluationof natural language for data retrieval. The natural language system andapplication are described along with the research design of the project.The results of the first part of the study, a laboratory experiment toinvestigate whether users perform better with an artificial or naturallanguage, suggest that after equal amounts of training no difference insubject performance is found between languages using a paper and penciltest . The insights gained to date are summarized. http://hdl.handle.net/2451/14600 Title: FORMAL SEMANTICS FOR TIME IN DATABASES<br/><br/>Clifford, James; Warren, David S.<br/><br/>Abstract: The concept of an historical database is introduced as a tool formodelling the dynamic nature of some part of the real world. Just asfirst-order logic has been shown to be a useful formalism for expressingand understanding the underlying semantics of the relational databasemodel, intensional logic is presented as an analogous formalism forexpressing and understanding the temporal semantics involved in anhistorical database. The various components of the relational model, asextended to include historical relations, are discussed in terms of themodel theory for the logic ILs, a variation of the logic IL formulatedby Richard Montague. The modal concepts of intensional and extensionaldata constraints and queries are introduced and contrasted. Finally, thepotential application of these ideas to the problem of Natural LanguageDatabase Querying is discussed. http://hdl.handle.net/2451/14599 Title: DEALER AND DEPARTMENT MANAGER PERFORMANCE AND THE USE OF AN INFORMATION SYSTEM<br/><br/>Lucas, Henry C., Jr.; Plimpton, Rodney B.<br/><br/>Abstract: It is important from an implementation standpoint to understand howinformation systems are used and what motivates individuals to use them.This paper presents the results of a study of dealership performance andthe use of a computer-based information system by an automobileimporter. The study reports results at the dealer and the departmentmanager level. Extensive performance data were available from themanufacturer while dealers and department managers completedquestionnaires. A descriptive model of information systems use andperformance guided the research. The results of the analysis suggestthat the use of reports is more strongly related to performance fordealers than for department managers. The dealer's style is associatedwith performance while dealer use of information and perceptions of thedealer's style are associated with department manager performance andinformation use. The implications of the study for decision makers andsystems designers are discussed. http://hdl.handle.net/2451/14598 Title: New Information Technology and Organizational Culture<br/><br/>Olson, Margrethe H.<br/><br/>Abstract: Predictions of the effects of office automation on organizations varywidely. This article focuses on changes in individual work patterns,management control, and organizational structure that may occur as aresult of implementation of office technology. The most significantchange predicted is that organizations will no longer be limited by acentral office work environment operating between the traditional officework hours of nine and five. Computer and communications technologywill facilitate the relaxing of those physical constraints asnecessitated by social and economic pressures. Relevant research todate regarding the effects of the new technology on organizationalbehavior is reviewed. Management guidelines for preparing for thecoming changes are included. http://hdl.handle.net/2451/14597 Title: NEW INFORMATION TECHNOLOGY AND ORGANIZATIONAL CULTURE<br/><br/>Olson, Margrethe H. http://hdl.handle.net/2451/14596 Title: QUERY LANGUAGES - A TAXONOMY<br/><br/>Vassiliou, Yannis; Jarke, Matthias http://hdl.handle.net/2451/14595 Title: QUERY PROCESSING STRATEGIES IN THE PASCAL/R RELATIONAL DATABASEMANAGEMENT SYSTEM<br/><br/>Jarke, Matthias; Schmidt, Joachim W.<br/><br/>Abstract: In the database programming language PASCAL/R, the programming languagePASCAL and concepts based on the relational data model are integrated.The paper investigates transformation strategies used in the PASCAL/Rsystem to evaluate queries with existential and universal quantifiers.Intermediate data structures are described using a high-level languagetool called a reference to a selected variable. The predicate calculusapproach used in PASCAL/R offers new insight into recently proposedquery optimization techniques and allows some of them to be extended. http://hdl.handle.net/2451/14594 Title: THE MEASUREMENT OF USER INFORMATION SATISFACTION<br/><br/>Ives, Blake; Olson, Margrethe H.; Baroudi, Jack Joseph<br/><br/>Abstract: This paper critically reviews measures of user information satisfactionand selects one for replication and extension. A survey of productionmanagers is used to provide additional support for the instrument,eliminate scales that are psychometrically unsound, and develop astandard short form for use when only an overall assessment ofinformation satisfaction is required and survey time is limited. http://hdl.handle.net/2451/14593 Title: DECISION SUPPORT SYSTEMS: ISSUES AND PERSPECTIVES<br/><br/>Ginzberg, Michael J.; Stohr, Edward A. http://hdl.handle.net/2451/14592 Title: SYSTEM RESPONSE TIME, OPERATOR PRODUCTIVITY AND JOB SATISFACTION<br/><br/>Barber, Raymond E.; Lucas, Henry C., Jr.<br/><br/>Abstract: This study examines the impact of on-line system response time on CRToperator productivity and job satisfaction. It was predicted thatincrease in response time would affect total transaction volume andtotal errors adversely, that is, total transaction volume would decreasewith longer response times and total errors would increase. Totalproductive transactions, the difference between total transactions andtotal errors, was expected to decrease as response time increased.Operator job satisfaction was also expected to decrease. The studyconfirmed the prediction with regard to total transactions andproductive transactions: both decreased as response time increased.Total errors actually decreased as response time increased, up to timesof 12 seconds. When response time exceeded 12 seconds, errorsincreased. The impact of response time on productivity suggests nearlyall transactions should be completed in 12 seconds or less. Beyond thislevel, the organization in the study suffered severe penalties in lostproductivity. A relationship was also found between increased responsetimes and reduced job satisfaction. http://hdl.handle.net/2451/14591 Title: RESEARCH IN NATURAL LANGUAGE RETRIEVAL SYSTEMS<br/><br/>Stohr, Edward A.; Turner, Jon A.; Vassiliou, Yannis; White, Norman H. http://hdl.handle.net/2451/14590 Title: A STRUCTURAL MODEL OF IMPLEMENTATION<br/><br/>Schultz, Randall L.; Ginzberg, Michael J.; Lucas, Henry C. , Jr.<br/><br/>Abstract: A general model of the management science implementation process ispresented based on the results of more than ten years of implementationresearch. A multiple-equation representation of that model is developedfor one important class of implementation, the two-stage implementation,in which it is necessary to gain both user and management acceptance ofthe system being implemented. The postulated model represents an advancein at least three ways: (a) it integrates previous findings; (b) itgeneralizes across settings; and (c) it is testable as a whole. http://hdl.handle.net/2451/14589 Title: A SHORT INTRODUCTION TO EXPERT SYSTEMS<br/><br/>Clifford, Jim; Jarke, Matthias; Vassiliou, Yannis http://hdl.handle.net/2451/14588 Title: ORGANIZATIONAL PERFORMANCE, SIZE, AND THE USE OF DATA PROCESSING RESOURCES<br/><br/>Turner, Jon A.<br/><br/>Abstract: This study addresses two issues-whether the size of an organizationdetermines its methods of obtaining, structuring or controlling dataprocessing resources, and whether organizational performance isinfluenced by how a firm makes use of these resources. Severalpropositions are tested using data from a sample of 58 mutual savingsbanks with a 10:1 range in size. The results suggest that, although nodifference is found in the proportion of operating expense allocated todata processing, larger banks do tend to develop in-house computingresources while smaller banks obtain these services from other banks orservice bureaus. Consequently large and small banks must resolvedifferent kinds of managerial issues if they are to provide high qualitydata processing service to their organizations. Unexpectedly, norelationship is found between organizational performance and therelative proportion of resources allocated to data operating cost andthe intensity of data processing use. These findings raise questionsabout the extent of benefits obtained from a data processing intensivestrategy as well as questions about the efficiency with which firmsconvert capital and labor into application systems. http://hdl.handle.net/2451/14587 Title: OVERVIEW OF WORK-AT-HOME TRENDS IN THE UNITED STATES<br/><br/>Olson, Margrethe H. http://hdl.handle.net/2451/14586 Title: SOFTWARE ERGONOMICS: EFFECTS OF COMPUTER APPLICATION DESIGN PARAMETERSON OPERATOR TASK PERFORMANCE AND HEALTH<br/><br/>Turner, Jon A.; Karasek, Robert A., Jr.<br/><br/>Abstract: Evidence is reviewed that the operating characteristics of computerapplication systems, in addition to physical characteristics of displayunits (CRTs), are the cause of many observed effects on operator healthand task effectiveness. These effects are hypothesized to occur throughchanges in task structure, and the man-machine redivision of labor thatresults when computer application systems are introduced into worksettings. First, the association between task dimensions and models ofoperator performance effectiveness and well-being are reviewed. Second,application system design parameters that affect task structure areidentified. Then, empirical evidence supporting this three part causallinkage - application system parameters to task characteristics tooperator effectiveness and health - is presented. The findings suggestthat by improving dialogue quality, taking advantage of two waycommunication to reduce uncertainty, using smaller and less integratedsystems and matching system performance to operator needs a job can becreated that is likely to improve both operator well-being and effectiveness. http://hdl.handle.net/2451/14585 Title: NATURAL LANGUAGE FOR DATABASE QUERIES: A LABORATORY STUDY<br/><br/>Vassiliou, Yannis; Jarke, Matthias; Stohr, Edward A.; Turner, Jon A.; White, Norman H.<br/><br/>Abstract: Are natural language systems for database queries meeting their goals?And, are these goals appropriate? The recently completed AdvancedLanguage Project at New York University combined a field experiment withtwo laboratory studies to examine these issues by comparing performancebetween subjects using the formal database language SQL and subjectsusing the prototype natural language system, USL. This paper describesthe design and results of the larger laboratory experiment. The resultspresented offer some promise for the usability of natural language undercertain conditions. http://hdl.handle.net/2451/14584 Title: COUPLING EXPERT SYSTEMS WITH DATABASE MANAGEMENT SYSTEMS<br/><br/>Jarke, Matthias; Vassiliou, Yannis<br/><br/>Abstract: The combined use of Database Management Systems (DBMS) and ArtificialIntelligence-based Expert Systems (ES) is potentially very valuable formodern business applications. The large body of facts usually requiredin business information systems can be made available to an ES throughan existing commercial DBMS. Furthermore, the DBMS itself can be usedmore intelligently and operated more efficiently if enhanced with ESfeatures. However, the implementation of a DBMS-ES cooperation is verydifficult. We explore practical benefits of the cooperative use of DBMSand ES, as well as the research challenges it presents. Strategies forproviding data from a DBMS to an ES are given; complementary strategiesfor providing intelligence from an ES to a DBMS are also presented.Finally, we discuss architechural issues such as degree of coupling, andcombination with quantitative methods. As an illustration, a researcheffort at New York University to integrate a logic-based business ESwith a relational DBMS is described. http://hdl.handle.net/2451/14583 Title: A KNOWLEDGE-BASED APPROACH TO THE ANALYSIS AND DESIGN OF BUSINESSTRANSACTION PROCESSING SYSTEMS<br/><br/>Jarke, Matthias; Shalev, Jacob<br/><br/>Abstract: In this paper, we propose a new approach to the analysis and design ofmanagement information systems. While previous methods were eithersyntactic in nature (structured analysis and design, problem statementlanguages) or focused on the user-analyst interaction (user-controlleddesign, prototyping), our method - while compatible with both -additionally incorporates the experiential knowledge gained from thethousands of systems in operation today. This goal is achieved throughproviding the systems analyst with a business systems architecture (BSA)consisting of two parts: a set of rules representing the knowledge abouta generalized application domain, and a domain-specific databasearchitecture that enforces these rules. The rules can also be used tocheck the design of existing systems and to guide the analysis processfor new systems. The paper describes a BSA for transaction processingsystems. The approach can be applied in a similar way to otherapplication domains such as decision support systems. http://hdl.handle.net/2451/14582 Title: TELECOMMUNICATIONS AND THE CHANGING DEFINITION OF THE WORKPLACE<br/><br/>Olson, Margrethe H.; Tasley, Roberta http://hdl.handle.net/2451/14581 Title: A DATABASE ARCHITECTURE FOR SUPPORTING BUSINESS TRANSACTIONS<br/><br/>Jarke, Matthias; Shalev, Jacob<br/><br/>Abstract: The central hypothesis of this paper is that database design and systemsdesign in general can be simplified considerably by tailoring the designmethods to a suitable range of applications. Domain-specific knowledgecan be incorporated into a specialized database architecture that leavesthe designer with the task to specify only the application-specificparts. Based on an analysis of business constraints, we propose such anarchitecture for the domain of business transaction processing. Thearchitecture offers several data and transaction management services,special-purpose sub-databases, and design checking rules to be used bythe application designer. Two services, input management and audit andcontrol services, are described in more detail. http://hdl.handle.net/2451/14580 Title: ACCESS TO SPECIFIC DECLARATIVE KNOWLEDGE BY EXPERT SYSTEMS: THE IMPACTOF LOGIC PROGRAMMING<br/><br/>Vassiliou, Yannis; Clifford, James; Jarke, Matthias<br/><br/>Abstract: As part of the operation of an Expert System, a deductive componentaccesses a database of facts to help simulate the behavior of a humanexpert in a particular problem domain. The nature of this access isexamined, and four access strategies are identified. Features of each ofthese strategies are addressed within the framework of a Logic-baseddeductive component and the relational model of data. http://hdl.handle.net/2451/14579 Title: RANGE NESTING: A FAST METHOD TO EVALUATE QUANTIFIED QUERIES<br/><br/>Jarke, Matthias; Koch, Jurgen<br/><br/>Abstract: Database queries explicitly containing existential and universalquantification become increasingly important in a number of areas suchas integrity checking, interaction of databases, and statisticaldatabases. Using a concept of range nesting in relational calculusexpressions, the paper describes evaluation algorithms andtransformation methods for an important class of quantified relationalcalculus queries called perfect expressions. This class includeswell-known classes of &quot;easy&quot; queries such as tree queries(with free and existentially quantified variables only), and complacent(disconnected) queries. http://hdl.handle.net/2451/14578 Title: ORGANIZATIONAL POWER AND THE INFORMATION SERVICES DEPARTMENT<br/><br/>Lucas, Henry C., Jr.<br/><br/>Abstract: A theory of intraorganizational power is discussed and applied to theinformation services department. The paper presents the results of astudy of the power of five departments in 40 manufacturing plants.Hypotheses about the levels of power of information processing are notsupported by the findings, however the power theory in general doesreceive support. Reasons for the unexpected results that the informationservices department is perceived as having low levels of power andinfluence in the organization are discussed. The paper suggests severalexplanations for the findings and possible problems in the organization.Recommendations to senior management and to the information servicesdepartment are offered. http://hdl.handle.net/2451/14577 Title: A MULTIDISCIPLINARY APPROACH TO INFORMATION SYSTEMS RESEARCH<br/><br/>Ariav, Gad; Clifford, James; Croker, Albert; Ginzberg, Michael J.; Jarke, Matthias; Laudon, Kenneth C.; Lucas, Henry C., Jr.; Olson, Margrethe H.; Reitman, Walter; Stohr, Edward A.; Turner, Jon A.; Uretsky, Myron; Vassiliou, Yannis; White, Norman http://hdl.handle.net/2451/14576 Title: IMPACT OF INFORMATION TECHNOLOGY ON WORK ORGANIZATION: A POSITIVE VIEW<br/><br/>Olson, Margrethe H. http://hdl.handle.net/2451/14575 Title: TOWARDS AN ALGEBRA OF HISTORICAL RELATIONAL DATABASES<br/><br/>Clifford, James<br/><br/>Abstract: In search of the appropriate semantics for the inclusion of structuresand operations that will meet the needs of a wide class of usersinterested in a database system supporting temporal views of their data,the paper includes a discussion of many problems that must be addressed.Salient features of the author&acirc;€™s Historical Relational DatabaseModel (HRDBM) are presented, and some subtle nuances that time brings tothe development of an historical relational algebra are illustrated.Along the way, a number of observations and guidelines are presentedthat may help guide the search for an historically relationally completedatabase model and query languages. http://hdl.handle.net/2451/14574 Title: IMPACT OF THE TECHNOLOGICAL ENVIRONMENT ON PROGRAMMER AND ANALYST JOB OUTCOMES<br/><br/>Baroudi, Jack J.; Ginzberg, Michael J. http://hdl.handle.net/2451/14573 Title: DSS DESIGN--A SYSTEMIC VIEW OF DECISION SUPPORT<br/><br/>Ariav, Gad; Ginzberg, Michael<br/><br/>Abstract: Current DSS research is rather fragmentary, and typically myopic--itcenters either on the decision situation which DSS support, or on DSStools or generators. In this paper we adopt a comprehensive view of DSSemphasizing their systemic nature. This entails identifying the linksamong the five aspects that classically characterize a system: 1, theenvironment, i.e., decision situations and access patterns; 2. thefunction (within this environment), i.e., types and levels of decisionsupport; 3. the functional components that make it up, i.e., dialog,data, and model management; 4. the arrangement, i.e., the linkages amongthe components and the assignment of functions to modules; and 5. theresources consumed, i.e., hardware, software, human skills, and data.The systemic view provides a concrete framework for the effective designof DSS, and serves as a basis for accumulating DSS research results. http://hdl.handle.net/2451/14572 Title: INFORMATION SYSTEMS AND COST CONTROL<br/><br/>Ginzberg, Michael J.; Shillinglaw, Gordon http://hdl.handle.net/2451/14571 Title: A DATA-DRIVEN USER INTERFACE GENERATOR FOR A GENERALIZED MULTIPLECRITERIA DECISION SUPPORT SYSTEM<br/><br/>Jarke, Matthias; Tawfik Jelassi, Mohamed; Stohr, Edward A. http://hdl.handle.net/2451/14570 Title: THE IMPACT OF ROLE VARIABLES ON INFORMATION SYSTEM PERSONNEL OUTCOMES:AN EMPIRICAL INVESTIGATION<br/><br/>Baroudi, Jack J.<br/><br/>Abstract: This study examines the antecedents of job satisfaction, commitment andturnover intentions for 229 information systems development personnel(ISDP) employed by nine companies within several industries. Theantecedents studied include boundary spanning, role ambiguity and roleconflict. A model of these variables is built and tested via pathanalysis. A secondary analysis is performed to explore the impacts oftask differences on the study variables. The task differences includeanalytic and programming tasks. The analyses revealed the following.Systems analysts span more boundaries than programmers. The major hazardfaced by systems analysts when they span boundaries is role conflictwhich negatively impacts their job satisfaction, commitment andintention to quit. The overall effect of boundary spanning is to reduceISDP intention to quit despite its positive relationship with roleconflict. Systems analysts and programmers are both intolerant of roleambiguity. Role ambiguity is very detrimental greatly reducing ISDP jobsatisfaction, commitment and increasing ISDP intention to quit. Roleambiguity is not related to boundary spanning nor is it related toanalytic or programming duties. Programmers are less committed thansystems analysts and are more likely to express intentions to leave. Theabove information is used to make recommendations to IS management.Finally, recommendations and directions are suggested regarding future research. http://hdl.handle.net/2451/14569 Title: COMPUTER MEDIATED WORK: THE INTERPLAY BETWEEN TECHNOLOGY AND STRUCTUREDJOBS - CLAIMS REPRESENTATIVES IN THE SOCIAL SECURITY ADMINISTRATION<br/><br/>Turner, Jon A.<br/><br/>Abstract: If general principles for the design of computer mediated work are toemerge, the interplay between the work environment and thecharacteristics of application systems must be understood better. Theresults of a study of 620 Claims Representatives in the Social SecurityAdministration, whose job differed only in the form of the applicationsystem interface used, are reported. Interactions with clients,operators&acirc;€™ perceived task environment and well being are allseen to be influenced by the type of system interface used. Mentalstrain symptoms is shown to be an important indicator of operator wellbeing. Implications for designers, managers and researchers are considered. http://hdl.handle.net/2451/14568 Title: DESIGNING A GENERALIZED MULTIPLE CRITERIA DECISION SUPPORT SYSTEM<br/><br/>Tawfik Jelassi, Mohamed; Jarke, Matthias; Stohr, Edward A.<br/><br/>Abstract: Decision support systems are of many kinds depending on the models andtechniques employed in them. Multiple criteria decision makingtechniques constitute an important class of DSS with unique softwarerequirements. This paper stresses the importance of interactive MCDMmethods since these facilitate learning through all stages of thedecision making process. We first describe some features of MultipleCriteria Decision Support Systems ( MCDSSs) that distinguish them fromclassical DSSs. We then outline a software architecture for a MCDSSwhich has three basic components: a Dialog Manager, an MCDM ModelManager, and a Data Manager. We describe the interactions that occurbetween these three software components in an integrated MCDSS andoutline a design for the Data Manager which is based on a concept oflevels of data abstraction. http://hdl.handle.net/2451/14567 Title: AN INVESTIGATION OF THE IMPACTS OF REMOTE WORK ENVIRONMENTS ANDSUPPORTING TECHNOLOGY<br/><br/>Olson, Margrethe H. http://hdl.handle.net/2451/14566 Title: Developing Strategic Information Systems<br/><br/>Turner, Jon A.; Lucas, Henry C., Jr. http://hdl.handle.net/2451/14565 Title: EXTERNAL SEMANTIC QUERY SIMPLIFICATION: A GRAPH-THEORETIC APPROACH ANDITS IMPLEMENTATION IN PROLOG<br/><br/>Jarke, Matthias<br/><br/>Abstract: Semantic query simplification utilizes integrity constraints enforced ina database system for reducing the number of tuple variables and termsin a relational calculus query. To a large degree, this can be done by asystem that is external to the DBMS. The paper advocates the applicationof database theory in such a system and describes a working prototype ofan external semantic query simplifier implemented in Prolog. The systememploys a graph-theoretic approach to integrate tableau techniques andalgorithms for the syntactic simplification of queries containinginequality conditions. The use of integrity constraints is shown notonly to improve efficiency but also to permit more meaningful errormessages to be generated, particularly in the case of an empty queryresult. The paper concludes with outlining an extension to themulti-user case. http://hdl.handle.net/2451/14564 Title: DATABASE ACCESS REQUIREMENTS OF KNOWLEDGE-BASED SYSTEMS<br/><br/>Vassiliou, Yannis; Clifford, Jim; Jarke, Matthias<br/><br/>Abstract: Knowledge bases constitute the core of those Artificial Intelligenceprograms which have come to be known as Expert Systems. An examinationof the most dominant knowledge representation schemes used in thesesystems reveals that a knowledge base can, and possibly should, bedescribed at several levels using different schemes, including thosetraditionally used in operational databases. This chapter providesevidence that solutions to the organization and access problem for verylarge knowledge bases require the employment of appropriate databasemanagement methods, at least for the lowest level of description -- thefacts or data. We identify the database access requirements ofknowledge-based or expert systems and then present four generalarchitectural strategies for the design of expert systems that interactwith databases, together with specific recommendations for theirsuitability in particular situations. An implementation of the mostadvanced and ambitious of these strategies is then discussed in some detail. http://hdl.handle.net/2451/14563 Title: INTRODUCTION TO QUERY PROCESSING<br/><br/>Jarke, Matthias; Koch, Jurgen; Schmidt, Joachim W.<br/><br/>Abstract: Query processing in databases can be divided into two steps: selectingan 'optimal' evaluation strategy, and executing it. We first presentelementary nested loop and relational algebra algorithms for queryexecution and point out some opportunities for improving theirperformance. A survey of optimization strategies, structured in querytransformation techniques and access planning methods, follows. Finally,extensions for special-purpose query systems are briefly addressed. http://hdl.handle.net/2451/14562 Title: STUDIES IN THE EVALUATION OF A DOMAIN-INDEPENDENT NATURAL LANGUAGE QUERY SYSTEM<br/><br/>Jarke, Matthias; Krause, Jurgen; Vassiliou, Yannis<br/><br/>Abstract: There is growing consensus that some of the most crucial questionsconcerning the feasibility and desirability of natural languageinterfaces to databases can only be resolved by empirical research.This paper reports the results of several empirical studies whichinvestigated the same domain-independent natural language query system,using various applications in two different natural languages - Englishand German. Taken together, these experiments involved about 100subjects and over 12,000 queries, constituting the bulk of empiricalevaluations of natural query language systems reported to date. Somedefinitive results are derived from the combined experience, and plansare outlined to resolve several of the remaining issues. http://hdl.handle.net/2451/14561 Title: COMMON SUBEXPRESSION ISOLATION IN MULTIPLE QUERY OPTIMIZATION<br/><br/>Jarke, Matthias<br/><br/>Abstract: The simultaneous optimization of multiple queries submitted to adatabase system may lead to substantial savings over the currentapproach of optimizing each query separately. Isolating commonsubexpressions in multiple queries and treating their execution as asharable resource are important prerequisites. This chapter presentstechniques for recognizing, supporting, and exploiting commonsubexpressions in record-oriented, relational algebra, domain relationalcalculus, and tuple relational calculus query representations. It alsoinvestigates preconditions that transaction management mechanisms mustsatisfy to make multiple query optimization effective.