Three essays on agricultural and environmental economics

This dissertation consists of three essays that explore the effects of biofuel and environmental policies on relevant industries. The first essay focuses on examining the market impacts and welfare consequences of U.S. biofuel policies. The second essay quantifies the U.S. agricultural supply response during the biofuel policy period. The third essay focuses on understanding the performance of a different kind of market-based policies in reducing industry-wide emissions. The U.S. renewable fuel standard (RFS), initiated in 2005 and extended in 2007, has been rationalized as pursuing, for example, reduction of greenhouse gas emission and reduction of the U.S. dependence on foreign energy sources. While its effects on food prices and actual environmental benefits remain controversial, the first essay constructs a multi-market equilibrium model and assesses the current and future economic effects of the RFS. The model integrates the U.S. agricultural sector with the energy sector and explicitly considers both U.S. ethanol and biodiesel production. The model is parameterized to represent observed 2015 data as status quo and then simulated to analyze alternative scenarios. The results confirm that the current RFS program considerably benefits the agricultural sector but also leads to overall welfare gains for the United States. Implementation of projected 2022 mandates, which would require further expansion of biodiesel production, would lead to a considerable welfare loss (relative to the status quo). While the abovementioned analysis relies on elasticities from the literature, the second essay directly quantifies the U.S. corn and soybean dynamic supply response. The RFS has been credited with being one of the main causes of (i) the recent global commodity price increases and (ii) the spatial changes in prices by affecting local basis nearby biofuel plants. The presence of these two demand-induced price effects provides an ideal opportunity to revisit the econometric analysis of the agricultural supply response. By focusing on recent years (2005-2015), therefore, the acreage and yield responses are estimated by using county-level panel data for the twelve Midwest states. The results indicate that the acreage and yield responses are highly inelastic. With relatively significant cross-price acreage elasticities, when corn and soybean prices move together, the response of the total acreage of these two key crops is very small. This result indicates that the ability of the U.S. corn and soybean production sector to accommodate the demand shock caused by the RFS is limited. As alternatives to command-and-control-type instruments such as mandates, market-based policies, such as voluntary agreement (VA) and Pigouvian tax, can be used to deal with environmental externalities. Given the increasing use of VAs, the third essay examines the performance of VA, relative to a tax policy and laissez faire policy, as a way to reduce environmental pollution. We find that when the market is non-competitive, the VA, relative to other policy options, improves welfare despite suffering from free-riding behavior. It is also found that as consumers value the green good more, the VA increases the number of green firms and provides a less competitive environment for free-riders, who increase the price of regular goods. As a result, the total market under the VA becomes less covered, at some point, than the tax policy. As for implementation, the potential gains from of the VA are attainable provided the regulator’s threat is credible and sufficiently strong

The Improvement of dam construction and maintenance through the 4th industrial revolution technologies

Thesis(Master) --KDI School:Master of Public Management,2018.The 4th Industrial Revolution is attracting attention as a new momentum for innovation growth that can simultaneously solve ''economic and social structural tasks'' based on the intelligent revolution. The 4th Industrial Revolution induces revolution in the national economy and society, including industrial terrain, employment structure, and people''s lives, and determines future competitiveness in accordance with successful responses. The rapid transition to the 4th industrial age is taking place in all fields not only in Korea but also all over the world. In particular, the construction industry is highly recognized as a 3D industry, and the inflow of younger people is very disadvantageous compared to other industries, and the technical manpower shortage is serious. In order to solve this problem, it is necessary to inject automation technology into the construction industry. In addition, the introduction of smart digital technology, such as acquiring accurate information, is absolutely necessary in order to efficiently manage aging dams and rapidly changing climates. Accordingly, K-water Dam construction and maintanance methods need to be improved by integrating ICT and IoT technologies appropriate for the 4th Industrial Age. Accordingly, K-water''s problems and solutions were proposed in order to introduce 4th Industrial Revolution Technologies through case studies in advanced countries.Chapter 1: Introduction Chapter 2: literature Review Chapter 3: Related Technology for 4th Industrial Revolution Chapter 4: Status of Promotion for 4th Industrial Revolution in Japan Chapter 5: Status of Promotion for 4th Industrial Revolution in Korea Chapter 6: Current Situation and Future Tasks in K-water Chapter 7: Conclusion & RecommendationmasterpublishedHyun Seok, KIM

Production of entanglement with highly-mixed states

We study production of entanglement with highly-mixed states. We find that entanglement between highly mixed states can be generated via a direct unitary interaction even when both states have purities arbitrarily close to zero. This indicates that purity of a subsystem is not required for entanglement generation. Our result is in contrast to previous studies where the importance of the subsystem purity was emphasized.Comment: 4 pages, 5 figure

On classical solutions of the compressible Navier-Stokes equations with nonnegative initial densities

We study the Navier-Stokes equations for compressible barotropic fluids in a bounded or unbounded domain $\Omega$ of $\mathbf{R}^3$. We first prove the local existence of solutions $(\rho, u)$ in $C([0,T_* ]; ( \rho^\infty + H^3 (\Omega ) ) \times ( D_0^1 \cap D^3 )(\Omega ) )$ under the assumption that the data satisfies a natural compatibility condition. Then deriving the smoothing effect of the velocity $u$ in $t>0$, we conclude that $(\rho , u)$ is a classical solution in $(0,T_{**}) \times \Omega$ for some $T_{**} \in (0, T_* ]$. For these results, the initial density needs not be bounded below away from zero and may vanish in an open subset ({\it vacuum}) of $\Omega$

Existence results for viscous polytropic fluids with vacuum

We consider the full Navier-Stokes equations for viscous polytropic fluids with nonnegative thermal conductivity. We prove the existence of unique local strong solutions for all initial data satisfying some compatibility condition. The initial density need not be positive and may vanish in an open set. Moreover our results hold for both bounded and unbounded domains

On the stationary Navier–Stokes equations in exterior domains

AbstractThis paper is concerned with the existence and uniqueness questions on weak solutions of the stationary Navier–Stokes equations in an exterior domain Ω in R3, where the external force is given by divF with F=F(x)=(Fji(x))i,j=1,2,3. First, we prove the existence and uniqueness of a weak solution for F∈L3/2,∞(Ω)∩Lp,q(Ω) with 3/2<p<3 and 1≤q≤∞ provided ‖F‖L3/2,∞(Ω) is sufficiently small. Here Lp,q(Ω) denotes the well-known Lorentz space. We next show that weak solutions satisfying the energy inequality are unique for F∈L3/2,∞(Ω)∩L2(Ω) under the same smallness condition on ‖F‖L3/2,∞(Ω). This result provides a complete answer to the uniqueness question of weak solutions satisfying the energy inequality, the existence of which was proved by Leray in 1933. Finally, we establish the existence of weak solutions for data F in a very large class, for instance, in L3/2(Ω)+L2(Ω), which generalizes Leray’s existence result