The impact of a wave farm on large scale sediment transport

This study investigates the interactions of waves and tides at a wave farm in the southwest of England, in particular their effects on radiation stress, bottom stress, and consequently on the sediment transport and the coast adjacent to the wave-farm (the Wave Hub). In this study, an integrated complex numerical modelling system is setup at the Wave Hub site and is used to compute the wave and current fields by taking into account the wave-current interaction, as well as the sediment transport. Results show that tidal elevation and tidal currents have a significant effect on the wave height and direction predictions; tidal forcing and wind waves have a significant effect on the bed shear-stress, relevant to sediment transport; waves via radiation stresses have an important effect on the longshore and cross-shore velocity components, particularly during the spring tides. Waves can impact on bottom boundary layer and mixing in the water column. The results highlight the importance of the interactions between waves and tides when modelling coastal morphology with presence of wave energy devices

Patent Protection, Technological Change and Wage Inequality

We develop a directed-technological-change model to address the issue of the optimal patent system and investigate how the optimal patent system influences the direction of technological change and the inequality of wage, where patents are categorized as skill- and labor-complementary. The major results are: (i) Finite patent breadth maximizes the social welfare level; (ii) Optimal patent breadth increases with the amount of skilled (unskilled) workers; (iii) Optimal patent protection is skill-biased, because an increase in the amount of skilled workers increases the dynamic benefits of the protection for skill-complementary patents via the economy of scale of skill-complementary technology; (iv) Skill-biased patent protection skews inventions towards skills, thus increasing wage inequality; And, (v) international trade leads to strong protection for skill-complementary patents, hence increasing skill premia.Patent Breadth, Skill-Biased Patent Protection, Skill-Biased Technological Change, Wage Inequality, Growth

Directed Technological Change: A Knowledge-Based Model

We develop a knowledge-based growth model to address the issues of directed technological change, wage inequality and economic growth, in which skilled workers are used both in innovation and production. Since skill-biased technological change may lead to a decrease in the average productivity in R&D sectors, scale effect is removed. Free trade between developed countries increases the demand for skilled workers employed in the production of the skill-intensive good, thus promoting skill-biased technological change through the market size e¡èect and an increase in skill premia. In contrast, free trade between developed and developing countries reduces the profits of skill-complementary innovation, since its market is relatively small in the developing country. Thus, international trade may lead to skill-replacing technological change and decrease wage inequality in the developed country. Wage inequality, however, increases in the developing countries since the degree of skill bias of technology in the developing country in the open economy is greater than the one in autarky. Skill-biased technological change has opposite e¡èects on economic growth, therefore trade stimulates economic growth in some circumstances, and hurts it in other circumstances.Directed Technological Change, Wage Inequality, Scale Effect, Trade, Growth