Error-correcting code on a cactus:A solvable model

An exact solution to a family of parity check error-correcting codes is provided by mapping the problem onto a Husimi cactus. The solution obtained in the thermodynamic limit recovers the replica-symmetric theory results and provides a very good approximation to finite systems of moderate size. The probability propagation decoding algorithm emerges naturally from the analysis. A phase transition between decoding success and failure phases is found to coincide with an information-theoretic upper bound. The method is employed to compare Gallager and MN codes.

The practice and process of delivering integration through strategic planning

This paper explains how strategic planning is able to deliver strategic integration within organizations. While communication and participation within planning processes are perceived to have an integrative effect, we argue that these effects are unlikely to arise simply from bringing people together. Rather, we suggest that, given the varying interests of actors in different business units, integration will only arise from active negotiations and compromises between these actors. The paper is based upon a case of strategic planning in a multinational that was attempting to develop greater strategic integration across Europe. Drawing upon an activity theory framework, we examine how a common strategy emerges over time through modifications to the planning process and to different actors’ roles within it. The findings are used to develop a process model that shows how different business unit characteristics of planning experience and relative power shape different experiences of communication and participation activities and different processes for achieving integration. The paper concludes with a discussion of how this process model contributes to the literature on strategic planning, political processes of strategy-making, and strategy-as-practice.

Comparative efficiency analysis of Portuguese bank branches

The advent of Internet banking and phone banking is changing the role of bank branches from a predominantly transaction-based one to a sales-oriented role. This paper reports on an assessment of the branches of a Portuguese bank in terms of their performance in their new roles in three different areas: Their efficiency in fostering the use of new transaction channels, their efficiency in increasing sales and their customer base, and their efficiency in generating profits. Service quality is also a major issue in service organisations like bank branches, and therefore we analyse the way this dimension of performance has been accounted for in the literature and take it into account in our empirical application. We have used data envelopment analysis (DEA) for the different performance assessments, but we depart from traditional DEA models in some cases. Performance comparisons on each dimension allowed us to identify benchmark bank branches and also problematic bank branches. In addition, we found positive links between operational and profit efficiency and also between transactional and operational efficiency. Service quality is positively related with operational and profit efficiency. © 2006 Elsevier B.V. All rights reserved.