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221.
Increasingly, customer companies hire external information technology (IT) consultants, often on a special project basis. These consultants are employees of professional service firms, although they receive their assignments from the hiring companies, report to them, and are supervised by them. Using semistructured interviews with 12 IT consultants in Sweden, we examine the factors that influence their work motivation, including the effect of this dual allegiance—to the service firm and to the customer company. The data indicate that the primary motivators are the variety in tasks and the opportunity to influence and/or manage an entire project. Neither monetary incentives nor the consultancy firm norms are strong motivators. A factor that affects work behavior and motivation is the subordinate identity that IT consultants must assume with their powerful clients. The article concludes with practical suggestions for managers who seek to understand what motivates employees who work at a distance, under external control. © 2011 Wiley Periodicals, Inc. 相似文献
222.
In graph mining, a frequency measure for graphs is anti-monotonic if the frequency of a pattern never exceeds the frequency of a subpattern. The efficiency and correctness of most graph pattern miners relies critically on this property. We study the case where frequent subgraphs have to be found in one graph. Vanetik et al. (Data Min Knowl Disc 13(2):243?C260, 2006) already gave sufficient and necessary conditions for anti-monotonicity of graph measures depending only on the edge-overlaps between the instances of the pattern in a labeled graph. We extend these results to homomorphisms, isomorphisms and homeomorphisms on both labeled and unlabeled, directed and undirected graphs, for vertex- and edge-overlap. We show a set of reductions between the different morphisms that preserve overlap. As a secondary contribution, we prove that the popular maximum independent set measure assigns the minimal possible normalized frequency and we introduce a new measure based on the minimum clique partition that assigns the maximum possible normalized frequency. In that way, we obtain that all normalized anti-monotonic overlap graph measures are bounded from above and below. We also introduce a new measure sandwiched between the former two based on the polynomial time computable Lovász ??-function. 相似文献
223.
Simulations of the interaction between a vortex and a NACA0012 airfoil are performed with a stable, high-order accurate (in space and time), multi-block finite difference solver for the compressible Navier-Stokes equations.We begin by computing a benchmark test case to validate the code. Next, the flow with steady inflow conditions are computed on several different grids. The resolution of the boundary layer as well as the amount of the artificial dissipation is studied to establish the necessary resolution requirements. We propose an accuracy test based on the weak imposition of the boundary conditions that does not require a grid refinement.Finally, we compute the vortex-airfoil interaction and calculate the lift and drag coefficients. It is shown that the viscous terms add the effect of detailed small scale structures to the lift and drag coefficients. 相似文献
224.
Events play many roles in computer systems, ranging from hardware interrupts, over event-based software architecture, to monitoring and managing of complex systems. In many applications, however, individual event occurrences are not the main point of concern, but rather the occurrences of certain event patterns. Such event patterns can be defined by means of an event algebra, i.e., expressions representing the patterns of interest are built from simple events and operators such as disjunction, sequence, etc.We propose a novel event algebra with intuitive operators (a claim which is supported by a number of algebraic properties). We also present an efficient detection algorithm that correctly detects any expression with bounded memory, which makes this algebra particularly suitable for resource-constrained applications such as embedded systems. 相似文献
225.
Rupert Wegerif Bruce M. McLaren Marian Chamrada Oliver Scheuer Nasser Mansour Jan Mikšátko Mriga Williams 《Computers & Education》2010
This paper reports on an aspect of the EC funded Argunaut project which researched and developed awareness tools for moderators of online dialogues. In this study we report on an investigation into the nature of creative thinking in online dialogues and whether or not this creative thinking can be coded for and recognized automatically such that moderators can be alerted when creative thinking is occurring or when it has not occurred after a period of time. We outline a dialogic theory of creativity, as the emergence of new perspectives from the interplay of voices, and the testing of this theory using a range of methods including a coding scheme which combined coding for creative thinking with more established codes for critical thinking, artificial intelligence pattern-matching techniques to see if our codes could be read automatically from maps and ‘key event recall’ interviews to explore the experience of participants. Our findings are that: (1) the emergence of new perspectives in a graphical dialogue map can be recognized by our coding scheme supported by a machine pattern-matching algorithm in a way that can be used to provide awareness indicators for moderators; (2) that the trigger events leading to the emergence of new perspectives in the online dialogues studied were most commonly disagreements and (3) the spatial representation of messages in a graphically mediated synchronous dialogue environment such as Digalo may offer more affordance for creativity than the much more common scrolling text chat environments. All these findings support the usefulness of our new account of creativity in online dialogues based on dialogic theory and demonstrate that this account can be operationalised through machine coding in a way that can be turned into alerts for moderators. 相似文献
226.
227.
Wil M. P. van der Aalst Marlon Dumas Florian Gottschalk Arthur H. M. ter Hofstede Marcello La Rosa Jan Mendling 《Formal Aspects of Computing》2010,22(3-4):459-482
A configurable process model captures a family of related process models in a single artifact. Such models are intended to be configured to fit the requirements of specific organizations or projects, leading to individualized process models that are subsequently used for domain analysis or solution design. This article proposes a formal foundation for individualizing configurable process models incrementally, while preserving correctness, both with respect to syntax and behavioral semantics. Specifically, assuming the configurable process model is behaviorally sound, the individualized process models are guaranteed to be sound. The theory is first developed in the context of Petri nets and then extended to a process modeling notation widely used in practice, namely Event-driven Process Chains. 相似文献
228.
Jan Smans Bart Jacobs Frank Piessens Wolfram Schulte 《Formal Aspects of Computing》2010,22(3-4):423-457
Framing in the presence of data abstraction is a challenging and important problem in the verification of object-oriented programs Leavens et al. (Formal Aspects Comput (FACS) 19:159–189, 2007). The dynamic frames approach is a promising solution to this problem. However, the approach is formalized in the context of an idealized logical framework. In particular, it is not clear the solution is suitable for use within a program verifier for a Java-like language based on verification condition generation and automated, first-order theorem proving. In this paper, we demonstrate that the dynamic frames approach can be integrated into an automatic verifier based on verification condition generation and automated theorem proving. The approach has been proven sound and has been implemented in a verifier prototype. The prototype has been used to prove correctness of several programming patterns considered challenging in related work. 相似文献
229.
Jan Recker 《欧洲信息系统杂志》2010,19(1):76-92
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. 相似文献
230.