Constrained Query Answering

Traditional answering methods evaluate queries only against positive and definite knowledge expressed by means of facts and deduction rules. They do not make use of negative, disjunctive or existential information. Negative or indefinite knowledge is however often available in knowledge base systems, either as design requirements, or as observed properties. Such knowledge can serve to rule out unproductive subexpressions during query answering. In this article, we propose an approach for constraining any conventional query answering procedure with general, possibly negative or indefinite formulas, so as to discard impossible cases and to avoid redundant evaluations. This approach does not impose additional conditions on the positive and definite knowledge, nor does it assume any particular semantics for negation. It adopts that of the conventional query answering procedure it constrains. This is achieved by relying on meta-interpretation for specifying the constraining process. The soundness, completeness, and termination of the underlying query answering procedure are not compromised. Constrained query answering can be applied for answering queries more efficiently as well as for generating more informative, intensional answers

The reforming appeal of distributed leadership

With a systematic literature review, this article examines the significance of distributed leadership in healthcare, assessing the extent to which it reflects a consistent set of values, meanings, practices and outcomes. It identifies key mediating factors and their importance in enabling or constraining distributive leadership processes. The findings indicate that clinicians without formal leadership titles are inspiring change and driving improvements, although countervailing pressures are limiting this in practice. Distributed leadership is evident in the way that clinical teams function, and more could be made of this for the modernisation of healthcare. At present, this potential tends to be constrained, and subject to competing interpretations that reflect distinct occupational identities. Greater attention could be given to educational and developmental programmes that claim space for distributed influence among current and aspiring leaders, and for enabling arrangements that can help ‘ordinary leaders’ to feel less vulnerable and more confident about this aspect of their practice. Established approaches to leader development could be usefully refocused to prioritise collective processes and refine relational abilities, ideally with more inclusive, joint venture initiatives that bring formal and informal leaders together for mutual learning and effective engagement

Cohesive subgroup formation: Enabling and constraining effects of social capital in strategic technology alliance networks

formation, subgroup, social capital

Transforming N-ary relationships to database schemas: an old and forgotten problem

The N-ary relationships, have been traditionally a source of confusion and still are. One important source of confusion is that the term cardinality in a relationship has several interpretations, two of them being very popular. But none of the two approaches, nor the two together, allow us to express all the possible cardinality patterns. The transformations from all the possible relationships to database schemas have never been described by the existing literature. Using the 14 ternary patterns as example, we discuss these transformations particularly the transformations from the patterns ignored in the literature.Postprint (published version

A Relational Account of the Causes of Spatial Firm Mobility

It is accepted in the literature that exchanges within networks have an ongoing social structure that both enables and constrains the behavior of its members (Pfeffer and Nowak 1976; Uzzi 1996). However, most research in inter-organizational settings has focused on the enabling effects of networks and network structures only, even though some noteworthy exceptions exist (e.g. Romo and Schwartz 1995; Singh and Mitchell 1996). A possible constraining effect of network participation is spatial lock-in, also known as spatial inertia, of a firm. Following Resource Dependence Theory (Pfeffer and Salancik 1978), it can be argued that a firm that makes extensive use of knowledge resources possessed or controlled by external actors for its innovative processes can become dependent on these actors. By themselves, the relationships in which these dependencies exist are non-spatial. However, since geographical proximity is assumed to facilitate the successful exchange of (especially tacit) knowledge through inter-organizational relationships (IORs) (Bretschger 1999), dependency on other firms located in the same region can also lead to dependency on a certain geographical location, and thus to spatial lock-in (Stam 2003). The IORs that are enabling for the firm in terms of its innovative processes act, at the same time, as constraining factors for the spatial behavior of the firm. Similar reasonings can be found in the literature on Territorial Innovation Models (Moulaert and Sekia 2003), which indicates that economic embeddedness in a region can be beneficial for the performance of firms. However, this embeddedness can also lead to dependence on localized inputs and production factors. Due to these dependencies, a firm can become very unlikely to relocate, even if doing so is beneficial from a cost perspective. As Romo and Schwartz state: “Firms are usually too dependent on the material, political and social resources available in the local production culture to risk departure, even when production costs might be substantially reduced (Romo and Schwartz 1995:874).†There currently is, however, only weak empirical evidence for the proposed relationship between the level of (local) embeddedness and a firm’s propensity to relocate. Moreover, several authors even propose that geographical distance in IORs is becoming irrelevant since it effects can be replicated by ICT (Morgan 2004), or high levels of organizational or technological proximity (Kirat and Lung 1999). If this is indeed the case, then participation in localized innovative IORs will have no effect on the spatial behavior of firms, since a firm can operate exactly the same on a different geographical location. The main goal of this research is to provide empirical insights into the effects of a firm’s level of participation in innovative (localized) inter-organizational relationships (IORs) on its propensity to relocate. Based on the above, the following research question has been formulated is “To what extent is the level of embeddedness of a firm in (localized) innovative inter-organizational relationships of influence on its propensity to relocate?†Answering this research question adds to the insights about the constraining effects of networks by focusing on the spatially constraining effect of inter-organizational relationships. This research question will be answered based on a data from a survey among Dutch automation service firms in 2006. In line with earlier research (c.f. Van Dijk and Pellenbarg 2000; Brouwer et al. 2004) an ordinal logit model will be used to relate the relocation propensity of a firm to that firm’s participation in localized innovative IORs, the strength of these IORs, and the level of geographical, organizational and technological proximity. It also provides insight into the question whether or not high levels of technological and organizational proximity can negate the need for geographical proximity in inter-organizational collaboration (Boschma 2005). References: Boschma, R. A. (2005). "Proximity and innovation: A critical assessment." Regional Studies 39(1): 61-74 Bretschger, L. (1999). "Knowledge diffusion and the development of regions." Annals of Regional Science 33(3): 251-268 Brouwer, A. E., I. Mariotti and J. N. van Ommeren (2004). "The firm relocation decision: An empirical investigation." Annals of Regional Science 38(2): 335-347 Van Dijk, J. and P. H. Pellenbarg (2000). "Firm relocation decisions in The Netherlands: An ordered logit approach." Papers in Regional Science 79(1): 191-219 Kirat, T. and Y. Lung (1999). "Innovation and proximity - Territories as loci of collective learning processes." European Urban and Regional Studies 6(1): 27-38 Morgan, K. (2004). "The exaggerated death of geography: Learning, proximity and territorial innovation systems." Journal of Economic Geography 89(1): 3-21 Moulaert, F. and F. Sekia (2003). "Territorial innovation models: A critical review." Regional Studies 37(3): 289-302 Pfeffer, J. and P. Nowak (1976). "Joint-ventures and interorganizational interdependence." Administrative Science Quarterly 21(3): 398-418 Pfeffer, J. and G. R. Salancik (1978). The external control of organizations: A resource dependency perspective. New York, Harper and Row Romo, F. P. and M. Schwartz (1995). "The structural embeddedness of business decisions: The migration of manufacturing plants in New York state, 1960 to 1985." American Sociological Review 60(1): 874-907 Singh, K. and W. Mitchell (1996). "Precarious collaboration: Business survival after partners shut down or form new partnerships." Strategic management journal 17(2): 99-116 Stam, F. C. (2003). Why butterflies don't leave: Locational evolution of evolving enterprises. Utrecht, Utrecht University Uzzi, B. (1996). "The sources and consequences of embeddedness for the economic performance of organizations: The network effect." American Sociological Review 61(4): 674-698