Previous research has argued that innovative activities should be concentrated in recessions. However, innovation, as measured by R&D expenditure, seems to concentrate in booms. We argue that R&D expenditures do not capture the different dimensions of firms’ innovative search strategies. We introduce a model of innovative exploration and exploitation over the business cycle and present supporti...

I develop a framework of the build-up and outbreak of financial crises in an asymmetric information setting. In equilibrium, two distinct economic states arise endogenously: normal times – periods of modest investment, and booms – periods of expansionary investment. Normal times occur when the intermediary sector realizes moderate investment opportunities. Booms occur when the intermediary sect...

Credit booms often cause economic expansions. But some credit booms end in financial crises yet others do not. To find out why, this paper presents a dynamic general equilibrium model of production economies with adverse selection in the financial market. Entrepreneurs can take on short-term collateralized debt and trade long-term assets to finance investment. Funding liquidity can erode market...

Telescopic booms are key elements for payload lifting in construction machineries. They usually consist of thin-walled hollow segments that can retract, extend or elevate during operation. The mechanical properties of the telescopic booms directly determine the lifting capacity of these machines. The overlapping contact regions between the adjacent booms are critical locations where high stress...

This paper presents a political economy theory of the behavior of fiscal policy over the business cycle. The theory predicts that, in both booms and recessions, fiscal policies are set so that the marginal cost of public funds obeys a submartingale. In the short run, fiscal policy can be pro-cyclical with government debt spiking up upon entering a boom. However, in the long run, fiscal policy i...

Development and infusion of break-through technologies is needed to enable better, faster and cheaper space missions to be flown in the future. One of these technologies, space inflatable structure, is currently receiving much attention. The use of space inflatable structures can potentially revolutionize the architecture and design of many large, lightweight space systems that must have extrem...

We study a dynamic economy where credit is limited by insu¢ cient collateral and, as a result, investment and output are too low. In this environment, changes in investor sentiment or market expectations can give rise to credit bubbles, that is, expansions in credit that are backed not by expectations of future pro…ts (i.e. fundamental collateral), but instead by expectations of future credit (...

The handling of complex machines such as redundant manipulators requires appropriate control systems in order to make the operating of the system easier and to reduce processing time. This paper presents an advanced control system for a drilling rig used in tunnel construction which is currently under development in cooperation with an industrial partner. The drill rig is equipped with two redu...