Estimating systems of trending variables

A survey is given of some results on inference in cointegrated systems. We discuss some regression methods, and contrast them with the analysis of the vector autoregressive model. We discuss determination of cointegrating rank and estimation of parameters, as well as asymptotic inference. The problems are treated for 1(1) and for 1(2) variables.     

Asymptotic Inference on Cointegrating Rank in Partial Systems

The likelihood ratio test for cointegrating rank is analyzed for partial (or conditional) systems in the vector autoregressive error-correction model. Under the assumption of weak exogeneity for the cointegrating parameters, the asymptotic distributions are given and tables of critical values are provided. A discussion is given of some of the assumptions of the model, why they are needed, and how they are tested.     

Asymptotic Theory of Outlier Detection Algorithms for Linear Time Series Regression Models

Outlier detection algorithms are intimately connected with robust statistics that down‐weight some observations to zero. We define a number of outlier detection algorithms related to the Huber‐skip and least trimmed squares estimators, including the one‐step Huber‐skip estimator and the forward search. Next, we review a recently developed asymptotic theory of these. Finally, we analyse the gauge, the fraction of wrongly detected outliers, for a number of outlier detection algorithms and establish an asymptotic normal and a Poisson theory for the gauge.     

Decision process in one-of-a-kind production

One-of-a-kind production is project business. In any project, the decision process is of importance for a successful outcome. However, there is a need for a more formal approach to decision-making in projects. We have therefore, developed a model of the decision process. It uses three types of decisions: selection, authorisation and plan decisions. Enterprise models together with the project life cycle form a platform for developing a decision model. The life cycle enables a decision chain, whereas the enterprise models allow decisions at different levels. The horizontal decision chain is linked to physical flow of documents and materials. Vertically, decision-making is hierarchically decomposed into levels of different planning horizons and time periods.     

A Small Sample Correction for the Test of Cointegrating Rank in the Vector Autoregressive Model

With the cointegration formulation of economic long–run relations the test for cointegrating rank has become a useful econometric tool. The limit distribution of the test is often a poor approximation to the finite sample distribution and it is therefore relevant to derive an approximation to the expectation of the likelihood ratio test for cointegration in the vector autoregressive model in order to improve the finite sample properties. The correction factor depends on moments of functions of the random walk, which are tabulated by simulation, and functions of the parameters, which are estimated. From this approximation we propose a correction factor with the purpose of improving the small sample performance of the test. The correction is found explicitly in a number of simple models and its usefulness is illustrated by some simulation experiments.     

Offshoring practices of Danish and Swedish SMEs: effects on operations configuration

This paper examines how small and medium enterprises (SMEs) configure their operations on the global scale and how this affects their home bases in terms of operations requirements and priorities. In order to relate SMEs’ offshoring initiatives with their operations configuration attributes, we draw on the operations networks literature and survey responses from 675 Danish and 410 Swedish companies. On the basis of the survey results, we find that although the SMEs are less experienced and less advanced in their offshoring ventures than large companies, they are building dispersed operations networks. Although still in their infancy, these networks are, as expected, creating new demands for their home bases in terms of demands for formalisation of work processes, systems development and managerial capability related to orchestrating operations across national borders, but more fundamentally, it also challenges the strategic foundations of the home base. Based on these observations, we discuss future global operations management challenges, practices and priorities of SMEs.