Explicit filters and supply chain design

Due to the complexity of present day supply chains it is important to select the simplest supply chain scheduling decision support system (DSS) which will determine and place orders satisfactorily. We propose to use a generic design framework, termed the explicit filter methodology, to achieve this objective. In doing so we compare the explicit filter approach to the implicit filter approach utilised in previous OR research the latter focusing on minimising a cost function. Although the eventual results may well be similar with both approaches it is much clearer to the designer, both why and how, an ordering system will reduce the Bullwhip effect via the explicit filter approach. The “explicit filter” approach produces a range of DSS designs corresponding to best practice. These may be “mixed and matched” to generate a number of competitive delivery pipelines to suit the specific business scenario.     

Time to default in the UK mortgage market

This paper employs duration analysis to investigate the timing of default in the UK mortgage market. Our analysis is performed on an ex ante basis, in that our explanatory variables are available to mortgage lenders when the loan is first made. We estimate both standard Weibull distributions and generalizations of the Weibull that permit non-monotonic hazard functions. The models fit the data well, suggesting that we have captured the major sources of variation in duration. We find that ‘cash flow’ variables, such as salary and interest rate paid, play the largest role. Surprisingly, loan-to-value ratios are either insignificant or influence default times in a counter-intuitive direction.     

Debt and managerial rents in a real-options model of the firm

We present a theory of capital investment and debt and equity financing in a real-options model of a public corporation. The theory assumes that managers maximize the present value of their future compensation (managerial rents), subject to constraints imposed by outside shareholders’ property rights to the firm's assets. Absent bankruptcy costs, managers follow an optimal debt policy that generates efficient investment and disinvestment. We show how bankruptcy costs can distort both investment and disinvestment. We also show how managers’ personal wealth constraints can lead to delayed investment and increased reliance on debt financing. Changes in cash flow can cause changes in investment by tightening or loosening the wealth constraints. Firms with weaker investor protection adopt higher debt levels.     

Networks and small business growth: An explanatory model

To date, there has been limited empirical research related to network theory. With this article, we have tried to fill this gap by testing an explanatory model of the impact of networks on small business growth. To analyze this causal relationship, the log-linear technique was used. The results suggest that networks have an influence on the growth of a small business, especially through contacts with national and international entrepreneurs.     

Intertemporal transfers of emission quotas in climate policies

We are interested in situations in which governments are committed to some pollution abatement constraint which does not match the society's most preferred level of pollution, like in the current climate change policies undergone on behalf of the Kyoto protocol. We develop an overlapping generations model with capital and pollution in which the individuals care about the environmental quality. We show that slightly improving the intertemporal flexibility of the emission quotas by authorizing two-period backward and forward transfers allows to decentralize the whole optimal growth path at competitive equilibrium.     

Public pensions and growth

This paper investigates the relationship between the size of an unfunded public pension system and economic growth in an overlapping generation economy, in which altruistic parents finance the education of their children and leave bequests. Unlike the existing literature, we model intergenerational altruism by assuming that children's income during adulthood is an argument of parental utility. Unfunded public pensions can promote growth when families face liquidity constraints preventing them from investing optimally in the education of their children. We consider two alternative ways of financing a public pension system, either by levying social contributions in a lump-sum manner or in proportion to labour income. We find that there is no case for unfunded public pensions in economies where bequests are operative. By contrast, there exists a growth-maximising size of the public pension system in economies where bequests are not operative and individuals are sufficiently patient.     

Product service systems: exploring operational practices

Increasingly, original equipment manufacturers (OEMs) are offering integrated solutions of products and services (product service systems (PSS)). To be successful in a service strategy, the OEM has to be able to provide services at a lower cost than the do-it-yourself alternative of the customer. We identify five service operations guidelines to achieve operational excellence in the field of PSS. The guidelines are based on a structured return-on-invested-capital analysis in collaboration with an OEM in the compressed air and generator industry (due to confidentiality reasons the OEM is referred to as AirGen). Each of the guidelines is cascaded into operational practices.