The Impact of Data Models and Task Complexity on End User Performance: An Experimental Investigation

The purpose of this study was to investigate similarities and differences in the quality of data representations produced by end-users using the relational model (RM), the extended entity-relationship model (EERM), and the object-oriented model (OOM). By performing laboratory experiments using MIS major students, quality was evaluated on five constructs of a data model (i.e. entity/object, descriptor, identifier, relationship and generalization hierarchy) and six facets of a relationship (i.e. unary one-to-one, unary one-to-many, binary one-to-one, binary one-to-many, binary many-to-many and ternary many-to-many-to-many).The research focused on two major issues: data model design and data model conversion. The first issue investigated the differences in user performance between the RM, the EERM and the OOM. The second investigated the differences in user performance between the RM and the relational conversions of the EERM and the OOM models. For the first issue, EERM and OOM scored much higher than the RM in correctness scores of binary one-to-many and binary many-to-many relationships, but only the EERM led to significance. The RM and OOM scored much higher than EERM for unary one-to-one relationships, however, only the RM resulted in significance. The OOM required significantly less time for task completion than EERM. For the second issue, RM and the relational conversion of OOM scored significantly higher than the relational conversion of EERM for unary one-to-one relationships

Principles of Query Visualization

Query Visualization (QV) is the problem of transforming a given query into a graphical representation that helps humans understand its meaning. This task is notably different from designing a Visual Query Language (VQL) that helps a user compose a query. This article discusses the principles of relational query visualization and its potential for simplifying user interactions with relational data.Comment: 20 pages, 12 figures, preprint for IEEE Data Engineering Bulleti

Query Optimization Technique in Relational Databases�

Computer Scienc

comparative ease of use of a diagrammatic vs an iconic query language

Abstract The importance of designing query systems which are effective and easy to use has been widelyrecognized in the database area. Also, it is well known that the adequacy of a system should be testedagainst actual users in a well monitored experiment. However, very few such experiments have beenconducted. The objective of our study is to measure and understand the comparative ease with whichsubjects can construct queries in two kinds of visual languages, one diagrammatic and the other iconic.More specifically, we are interested in determining if there is significant interaction between: 1) the queryclass and the query language type; and 2) the type of query language and the experience of the user.Experimental results indicate that the effectiveness of a diagrammatic or an iconic query language variesdepending on the classes of queries and the kinds of users. This supports the opinion that an interfaceoffering to the user various visual representations and query modalities is the most appropriate for a wide setof users and applications.Keywords: Human-Computer Interaction; Query Languages; Visual Interfaces; Usability; Experiment

Logiikkapohjainen lähestymistapa RDF-tietolähteen esittämiseksi

Semanttinen verkko on internetin laajennos, jossa internetsivuille lisätään tietoa niiden sisällön merkityksestä sellaisessa muodossa, jonka tietokone voi ymmärtää. Tämä tieto esitetään käyttäen RDF-tietomallia ja sen laajennoksia. Semanttisessa verkossa tietolähteet yksilöidään antamalla niille URI-osoitteet. RDF-tietomalli on graafi, joka koostuu näistä URI-osoitteista, niihin liittyvistä arvoista ja niiden välisistä suhteista. RDF-graafi ilmaistaan kolmikkoina, joiden elementit ovat subjekti, predikaatti ja objekti. Subjekti on URI, objekti on URI tai arvo. Predikaatti kertoo subjektin ja objektin suhteen. Tässä tutkielmassa kehitetään uusi relaatioesitys RDF-tietolähteelle. Lisäksi verrataan kyselyjen tekemistä uudella tavalla esitettyyn tietoon ja kyselyjen tekemistä jo olemassa olevilla ratkaisuilla. Vertailukohteet ovat SPARQL ja SWI-Prolog-kielen valmispredikaatit RDF-tiedon käsittelyyn. Kyselyjä tehdessä tutkitaan sitä, millaisia kyselyjä voidaan toteuttaa ja sitä kuinka vaikea käyttäjän on niitä toteuttaa. Tulokset osoittavat, että kehitetty tapa mahdollistaa sellaisten kyselyjen tekemisen, joihin SPARQL ja SWI-Prolog-kielen valmispredikaatit eivät pysty ilman RDF-mallin laajennuksia. Käytettävyydeltään mikään ratkaisuista ei erotu erityisesti edukseen

Kahden XML-kyselykielen vertaileva käyttäjätutkimus

XML-merkatun tiedon tehokasta käsittelyä ja hakua varten on kehitetty relaatiotietokantojen SQL-kieltä vastaavia kyselykieliä. Tutkielmassa tarkastellaan kahden, lähtökohdiltaan ja ilmaisuvoimaltaan erilaisen XML-kyselykielen soveltuvuutta vuorovaikutteiseen ad hoc -käyttöön. Vertailuparina käytetään XQuery ja XIL-kieliä, joiden kummankin suunnittelussa on otettu vaikutteita relaatiotietokantojen SQL-kyselykielestä. Kieliä tarkastellaan erityisesti dokumenttiorientoituneen XML-tiedonhaun näkökulmasta. Tutkielmassa selvitetään ad hoc -käyttötilannetta jäljittelevien käyttäjäkokeiden avulla, tarjoaako ad hoc -käyttöön suunniteltu XIL käyttäjälleen hyötyä verrattaessa sitä yleiskäyttöiseen XQuery-kieleen. Kieliä verrataan suhteessa koetilanteissa annettujen oikeiden vastauksien määrään sekä vastauksissa tehtyjen virheiden määrään ja laatuun. Käyttäjäkokeiden tulosten sekä tutkimuskirjallisuuden pohjalta esitetään XIL-kieltä koskevia kehitysehdotuksia. Saadut tulokset kuvaavat testatuilla kielillä saavutettavaa suoriutumistasoa käyttötilanteessa, jossa tiedonhakija joutuu muotoilemaan kyselyn muistinvaraisesti ilman käyttöliittymän tai dokumentaation tukea. Mikäli XIL-kieltä halutaan kehittää tässä tutkielmassa esitettyjen kehitysehdotusten pohjalta, käyttäjäkokeiden tulokset tulisi validoida uusintatestillä mahdollisimman todenmukaisessa käyttöliittymässä. Asiasanat:tiedonhakujärjestelmät, käyttäjäkokeet, kyselykielet, XML, loppukäyttäjäohjelmoint

Query Processing on the Entity-Relationship Graph Based Relational Database Systems.

An ERG (Entity-Relationship Graph) can be used to provide a semantic structure to a relational database system. An ERG is defined by local regions. A local region contains two nodes of entity types and a node of relationship type. The semantic constraints of the database represented by the ERG (Entity-Relationship Graph) can be used to enforce the global integrity of the database system. A query is mapped onto the ERG to obtain an ERQG (Entity-Relationship Query Graph). This mapping can be specified by the user by navigating the database or automatically allocated by the system via a universal relation interface. The ERQG representation of a query can be semantically decomposed into a sequence of Local Regions. These Local Regions can then be processed according to their order in the query. The ER-semijoin operation is introduced to process this sequence of Local Regions. Using this approach, architectures of database systems are proposed--two-phase interface and one-phase interface. An implementation of a user interface is also discussed

A browser-based tool for designing query interfaces to scientific databases

Scientists in the biological sciences need to retrieve information from a variety of data collections, traditionally maintained in SQL databases, in order to conduct research. Because current assistant tools are designed primarily for business and financial users, scientists have been forced to use the notoriously difficult command-line SQL interface, supplied as standard by most database vendors. The goal of our research has been to establish the requirements of scientific researchers and develop specialized query assistance tools to help them query data collections across the Internet. This thesis describes our work in developing HyperSQL, a Web-to-database scripting language, and most importantly, Query Designer, a user-oriented tool for designing query interfaces directly on Web browsers. Current browsers (i.e., Netscape, Internet Explorer) do not easily interoperate with databases without extensive "CGI" (Common Gateway Interface) programming. HyperSQL is a scripting language that enables database administrators to construct forms-based query interfaces intended for end-users who are not proficient with SQL. Query results are formatted as hypertext-clickable links which can be used to browse the database for related information, bring up Web pages, or access remote search engines. HyperSQL query interfaces are independent of the database computer, making it possible to construct different interfaces targeting distinct groups of users. Capitalizing on our experience with HyperSQL, we developed Query Designer, a user-oriented tool for building query interfaces directly on Web browsers. No experience in SQL and HTML programming is necessary. After choosing a target database, the user can build a personalized query interface by making menu selections and filling out forms--the tool automatically establishes network connections, and composes HTML and SQL code. The automatically generated query form can be used immediately to issue a query, customized, or saved for later use. Results returned from the database are dynamically formatted into hypertext for navigating related information in the database

Development of a construction methodology of goal directed, optimal complexity, flexible and task oriented (GOFT) training materials for novice computer users: application and evaluation in adults with mental health problems

A number of information technology schemes have been developed in order to provide people with mental health problems the opportunity to acquire skills in micro-computer technology. Even though positive results have been reported a high incidence of dropouts during the beginning of the training have been found. The research is based on the assumption that in order for a computer training method to be effective in fostering computer skills and confidence to adult novice users with mental health problems has to: (a) bridge the gap between the user's capacities, needs, and preferences and the demands of the computer interfaces and their real task applications; (b) consider the ways adult novice users prefer to learn and the skill acquisition theories; (c) facilitate a goal directed interaction with the computer system; (d) maintain an optimal complexity level across training; and (e) allow flexibility of use. Based on the relevant literature, a methodology model and a set of design propositions and construction guidelines have been derived and have been implemented for the development of Goaldirected, optimal complexity, Flexible & Task oriented (GOFT) training materials for adult, novice users with mental health problems. The GOFT training materials were based on three different models, the one for the creation of a goal directed instruction format and the other two for the organisation of the training, and the estimation of the difficulty level of each new computer operation or real task application. Evaluation of use of the GOFT Training Materials by 34 adult, novice users (aged 18-51) with mental health problems revealed positive results. More specifically, the use of the GOFT training materials as compared to traditional methods resulted in a significant increase in the number of participants at the different training stages (85.3% versus 47.2%; and 44.5% versus 22.2% at three and twelve months respectively), in perfect & regular attendance rate ( 44,12% versus 11.11% & 32.35% versus 16.67%) and in the performance level (means of 3.75 versus 2.67) of the users. The subjective evaluation by the users also revealed significant differences between the GOFT and traditional training materials. In their evaluation the GOFT materials were rated significantly higher in terms of systematic arrangement, personal affect, understandability, task relevance, fitness, sense of control, confidence in using the mastered functions and in supporting goal directed learning approach