n an infinite horizon optimal control problem, the Hamiltonian vanishes at the infinite horizon, when the differential equation is autonomous. The integrand in the integral criterion may contain the time explicitly, but it has to satisfy certain integrability conditions. A generalization of...

Piecewise deterministic control problems are problems involving stochastic disturbance of a special type. In certain situations, in an otherwise deterministic control system, it may happen that the state jumps at certain stochastic points of time. Examples are sudden oil finds, or sudden...

In the past, environmental decision making has been based on analysis of policy options with respect to emission reduction, deposition or concentration of pollutants and the design of preventive strategies using disparate single-model and discipline results. It was impossible to obtain optimal...

The 1990 Canadian long-range transport of air pollutants and acid deposition report divided North America into 40 sources of emission and 15 sensitive receptor sites. For the purpose of national policy making and international negotiation, the use of these large sources and few receptors may...

In the past environmental management practices have been based on disparate analysis of the impacts of pollutants on selected components of ecosystems. However, holistic analysis of emission reduction strategies is necessary to justify that actions taken to protect the environment would not...

In the past environmental management practices have been based on disparate analysis of the impacts of pollutants on selected components of ecosystems. However, holistic analysis of emission reduction strategies is necessary to justify that actions taken to protect the environment would not...

The 1990 Canadian long-range transport of air pollutants and acid deposition report divided North America into 40 sources of emission and 15 sensitive receptor sites. For the purpose of national policy making and international negotiation, the use of these large sources and few receptors may...

We use Norwegian register data from 1989 to 2002 to estimate the causal effects of programme participation on the transition rate from unemployment to employment,by means of a dependent risks hazard rate model. The separate roles of causality and unobserved heterogeneity are non-parametrically...

Based on a combined register database for Norwegian and Swedish unemployment spells, we use the ‘between-countries-variation’ in the unemployment insurance systems to identify causal effects. The elasticity of the job hazard rate with respect to the benefit replacement ratio is around -1.0...

Building on register data describing monthly labour market status for the whole Norwegian population 1992-95, we estimate grouped competing risk hazard rate models for transitions between employment, unemployment and non-participation. The models impose no parametric restrictions on either...