Queries with CASE expressions

In recent years more and more queries are generated automatically by query managers/builders with end-users providing only specific parameters through GUIs. Queries generated automatically can be quite different from queries written by humans. In particular, they contain non-declarative features, most notorious of which is the CASE expression. Current query optimizers are often ill-prepared for the new types of queries as they do not deal well with procedural ‘insertions’. In this paper, we discuss the inefficiencies of CASE expressions and present several new optimization techniques to address them. We also describe experimental evaluation of the prototype implemented in DB2 UDB V8.2.     

Second-Order Abstract Categorial Grammars as Hyperedge Replacement Grammars

Second-order abstract categorial grammars (de Groote in Association for computational linguistics, 39th annual meeting and 10th conference of the European chapter, proceedings of the conference, pp. 148–155, 2001) and hyperedge replacement grammars (Bauderon and Courcelle in Math Syst Theory 20:83–127, 1987; Habel and Kreowski in STACS 87: 4th Annual symposium on theoretical aspects of computer science. Lecture notes in computer science, vol 247, Springer, Berlin, pp 207–219, 1987) are two natural ways of generalizing “context-free” grammar formalisms for string and tree languages. It is known that the string generating power of both formalisms is equivalent to (non-erasing) multiple context-free grammars (Seki et al. in Theor Comput Sci 88:191–229, 1991) or linear context-free rewriting systems (Weir in Characterizing mildly context-sensitive grammar formalisms, University of Pennsylvania, 1988). In this paper, we give a simple, direct proof of the fact that second-order ACGs are simulated by hyperedge replacement grammars, which implies that the string and tree generating power of the former is included in that of the latter. The normal form for tree-generating hyperedge replacement grammars given by Engelfriet and Maneth (Graph transformation. Lecture notes in computer science, vol 1764. Springer, Berlin, pp 15–29, 2000) can then be used to show that the tree generating power of second-order ACGs is exactly the same as that of hyperedge replacement grammars.     

Automata for Epistemic Temporal Logic with Synchronous Communication

We suggest that developing automata theoretic foundations is relevant for knowledge theory, so that we study not only what is known by agents, but also the mechanisms by which such knowledge is arrived at. We define a class of epistemic automata, in which agents’ local states are annotated with abstract knowledge assertions about others. These are finite state agents who communicate synchronously with each other and information exchange is ‘perfect’. We show that the class of recognizable languages has good closure properties, leading to a Kleene-type theorem using what we call regular knowledge expressions. These automata model distributed causal knowledge in the following way: each agent in the system has a partial knowledge of the temporal evolution of the system, and every time agents synchronize, they update each other’s knowledge, resulting in a more up-to-date view of the system state. Hence we show that these automata can be used to solve the satisfiability problem for a natural epistemic temporal logic for local properties. Finally, we characterize the class of languages recognized by epistemic automata as the regular consistent languages studied in concurrency theory.     

Knowledge Management in Locating the Patient in an Emergency Medical Service in Italy

This study examines an Emergency Medical Service in order to analyze the composite set of activities and instruments directed at locating the patient. The good management of information about the location of the emergency is highly relevant for a reliable rescue service, but this information depends on knowledge of the territory that is socially distributed between EMS operators and callers. Accordingly, the decision-making process often has to go beyond the emergency service protocols, engaging the operator in undertaking an open negotiation in order to transform the caller’s role from layman to “co-worker”. The patient’s location turns out to be an emerging phenomenon, collaborative work based on knowledge management involving two communities—the callers and the EMS operators—that overlap partially. Drawing examples from emergency calls, the study analyzes the practice of locating a patient as a complex and multi-layered process, highlighting the role played by new and old technologies (the information system and the paper maps) in this activity. We argue that CSCW technologies enable the blended use of different kinds of instruments and support an original interconnection between the professional localization systems and the public’s way of defining a position.     

Continued use of process modeling grammars: the impact of individual difference factors

Process modeling grammars are used by analysts to describe information systems domains in terms of the business operations an organization is conducting. While prior research has examined the factors that lead to continued usage behavior, little knowledge has been established as to what extent characteristics of the users of process modeling grammars inform usage behavior. In this study, a theoretical model is advanced that incorporates determinants of continued usage behavior as well as key antecedent individual difference factors of the grammar users, such as modeling experience, modeling background and perceived grammar familiarity. Findings from a global survey of 529 grammar users support the hypothesized relationships of the model. The study offers three central contributions. First, it provides a validated theoretical model of post-adoptive modeling grammar usage intentions. Second, it discusses the effects of individual difference factors of grammar users in the context of modeling grammar usage. Third, it provides implications for research and practice.     

Project failure <Emphasis Type="Italic">en masse</Emphasis>: a study of loose budgetary control in ISD projects

This paper investigates the tightness of budgetary control over projects in a large systems development multinational. This represents a case of extreme information systems development (ISD) failure en masse, where all but two of the 22 projects in a business unit went over budget, causing senior executives to refocus their strategic priorities and cancel all current and potential projects that followed. This study focuses specifically on the two best performing (12 and 4% under budget) and worst performing (223 and 320% over budget) of these projects. Using a framework drawn from control systems theory, this study examines the ‘tightness’ of budgetary control exerted over each project, and what was done or could have been done to avert such failure. The study then identifies a set of emerging factors affecting tight budgetary control in ISD.     

Do organisational and environmental factors moderate the effects of Internet-based interorganisational systems on firm performance?

We developed a model of the relationships among several organisational, interorganisational and technological factors, the adoption of Internet-based interorganisational systems (IBIS) and various measures of firm performance. We used structural equation modelling to empirically test these relationships. The findings showed that adopting IBIS indirectly improves the operational performance of firms through business process performance. The positive effect on financial performance of adopting IBIS is not direct, but through the mediating effects of operational performance and business process performance. We also utilised multiple group analysis to test some of the model relationships across firms using several organisational and environmental factors as moderators. The organisational factors tested are firm type, age and ownership type. The environmental factors consisted of dynamism, complexity and hostility. We found that the organisational factors are significant moderators and that complexity and hostility are not significant moderators. However, the effects of dynamism as a moderator are less clear.     

Managing as designing: ‘opportunity knocks’ for the IS field?

In response to anxieties about our discipline's decline, this opinion piece ‘looks to the future’, arguing a strong prospectus for the IS field, based on its direct relevance to general management practice. The thesis set out is inspired by the recent upsurge in interest in ‘managing as designing’. Reformulating management as design, I argue that we have a formidable knowledge-base of tools, theories and critique relevant to any manager, not just the MIS-inclined specialist. A case study of yet another failed information system (in U.K. children's services) is presented to show just how uniquely relevant our discipline is, in the workplace of today. Other pertinent issues are explored, such as synergies with the growing vogue for evidence-based management. The paper concludes by considering implications for research, including the need for a less exclusive approach to publishing and dissemination emphasising the need to make our work more accessible to lay practitioners.     

My social networking profile: copy,resemblance, or simulacrum? A poststructuralist interpretation of social information systems

This paper offers an introduction to poststructuralist interpretivist research in information systems, through a poststructuralist theoretical reading of the phenomenon and experience of social networking websites, such as Facebook. This is undertaken through an exploration of how loyally a social networking profile can represent the essence of an individual, and whether Platonic notions of essence, and loyalty of copy, are disturbed by the nature of a social networking profile, in ways described by poststructuralist thinker Deleuze's notions of the reversal of Platonism. In bringing a poststructuralist critique to such hugely successful and popular social information systems, the paper attempts to further open up the black box of the computer ‘user’, extend interpretive approaches to information systems research to embrace poststructuralism, and explore how notions of the Self might be reflected through engagement with information system (IS), and how an IS appreciation of the phenomenon of global social networking may benefit from embracing such a poststructuralist approach.