Coordinate sampler: a non-reversible Gibbs-like MCMC sampler

We derive a novel non-reversible, continuous-time Markov chain Monte Carlo sampler, called Coordinate Sampler, based on a piecewise deterministic Markov process, which is a variant of the Zigzag sampler of Bierkens et al. (Ann Stat 47(3):1288–1320, 2019). In addition to providing a theoretical validation for this new simulation algorithm, we show that the Markov chain it induces exhibits geometrical ergodicity convergence, for distributions whose tails decay at least as fast as an exponential distribution and at most as fast as a Gaussian distribution. Several numerical examples highlight that our coordinate sampler is more efficient than the Zigzag sampler, in terms of effective sample size.     

Why good practice of OR is not enough—Ethical challenges for the OR practitioner

This paper develops the idea that following rules of good OR practice is necessary, but not sufficient for ethical OR. Several challenges of introducing ethical aspects into OR are discussed, evidencing difficulties and ambiguities in the relationship to be established between the OR practitioner and his/her clients, decision-makers or stakeholders. It shows that neither analysis nor modelling work nor the choice of analytical tools is entirely ethically neutral; incomparability, incommensurability and incertitude must be dealt with. The purpose of this article is to detail several difficulties or dilemmas an OR practitioner may be confronted with in the course of his or her assignment. In such situations, following rules of good practice may not be sufficient to indicate how to act in a morally good way. This paper aims at stimulating reflection by structuring the debate; it may leave the reader unsettled—unsettlement being a result and even aim of many discussions in moral philosophy.     

Situational leadership theory: A test of three versions

Three versions of the leadership dynamics derived from Hersey and Blanchard's Situational Leadership Theory were identified: (1) the original, 1972, statement of the theory; (2) the revised, 2007, theory; and (3) an alternative statement of the theory's essential principle of differential follower response to “autonomy afforded by the leader” in conjunction with “follower developmental level” (as indexed by employee job experience). Survey data collected from 357 banking employees and 80 supervisors, sampled from 10 Norwegian financial institutions, were analyzed for predicted interactions. Results indicated that the 2007 revised theory was a poorer predictor of subordinate performance and attitudes than the original version. The third, alternative, version (which predicted an autonomy × job experience interaction) offered promise for further exploration of the theory's essential principle that employee outcomes are associated with prescribed leader behaviors in combination with follower developmental level, although this version also did not add substantially to accounting for criterion variance.     

A General Formula for Valuing Defaultable Securities

Previous research has shown that under a suitable no‐jump condition, the price of a defaultable security is equal to its risk‐neutral expected discounted cash flows if a modified discount rate is introduced to account for the possibility of default. Below, we generalize this result by demonstrating that one can always value defaultable claims using expected risk‐adjusted discounting provided that the expectation is taken under a slightly modified probability measure. This new probability measure puts zero probability on paths where default occurs prior to the maturity, and is thus only absolutely continuous with respect to the risk‐neutral probability measure. After establishing the general result and discussing its relation with the existing literature, we investigate several examples for which the no‐jump condition fails. Each example illustrates the power of our general formula by providing simple analytic solutions for the prices of defaultable securities.     

Understanding information systems infrastructure in engineering SMEs: A case study

The benefits of integrated enterprise-wide information systems (IS), such as Enterprise Resource Planning (ERP) systems, are widely accepted. The implementation of such systems in large organisations is established with many in their second or third generation. However, in small to medium-sized enterprises (SMEs) the maturity and extent of their IS infrastructure is less clear. In engineering SMEs, this infrastructure needs to support not only business processes but also the activities of design and manufacture.In this case study, our goal is to provide a better understanding of current IS infrastructure, the functional elements of IS infrastructure, integration and expenditures are explored in ten engineering SMEs. A model of IS functionality is developed and used to identify and classify functional elements within the firms and to compare and contrast the IS infrastructures. The findings are contrasted with the SME literature and conclusions and implications developed.     

Self-management competencies in self-managing teams: Their impact on multi-team system productivity

This research examined how composition of individual capabilities within self-managed teams translates into greater effectiveness for multi-team systems (MTS) in which teams are embedded. We investigated how a broad range of self-management competencies by team members aggregate to form a collective construct that influences productivity of a team network. In a semiconductor plant, we surveyed 716 members from 97 self-managed teams in 21 MTS. We found that MTS comprising teams whose members widely practice self-management strategies attain higher productivity gains and that multi-team systems consisting of highly cohesive teams of self-managers are the most productive.