Optimal exploitation of common property resources: a case of groundwater mining in the Ogallala Aquifer

Water shortage is one of the most serious long-range problems for the United States, as has been witnessed in recent years. With rising energy costs and declining water tables, it appears that the U.S. agricultural sector faces the problem of how to efficiently allocate limited groundwater resources intertemporally and spacially;At first, theoretical aspects of common property resources are discussed. A model of production using common property resources is built. It focuses on factors determining intertemporal exploitation patterns of common property resources and on a comparison of a social optimal and a free market model. The theoretical analysis implies that, first, the lower the discount rate the larger the change of the exploitation rate, second, the greater the stock externality the greater the change of the exploitation rate, third, the steeper the slope of the yield function, the larger the change of the exploitation path, and fourth, the better the resource grade the more the resource will be exploited;Based on the theoretical analysis, the dynamic model is applied in the Southern Ogallala Aquifer. The solutions provide optimal rates of water use, irrigation acreages, farm income, net present values of farm income, and the levels of water tables for each of the 144 resource situations for years 1985-2005 under five alternative scenarios, with respect to energy and crop prices and discount rates. Comparing the social optimal solution with the free market solution, economic losses and excessive depletions of water due to commonality are estimated. The social optimal solution has a higher net farm income than the free market solution, and more water is conserved under the social optimal solution. With the free market policy, the region will lose 70 million in net farm income and 2.9 feet of its water table under the base scenario. Losses, however, depend on energy levels, crop prices, and the discount rate. Three alternative policies for achieving social optimal allocation of resources are examined. They are the flexible taxation in which the tax rate changes every five years, the fixed taxation which is constant over periods, and the quota policy. Examining the benefits side only, the experimental results for the Ogallala Aquifer prove that the flexible taxation is the best policy

A room in the room : a private spectacle

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2000.Includes bibliographical references (leaves 40-41)."A Room in the Room" is a temporary site-specific installation in which I constructed a room inside of my private room, located at 352 Marlborough Street in Boston. The inner room, accessible by the second door of my room, forms an enclosure made out of transparent glass walls. Visitors enter the inner room to share my visual and sound experiences, but not physically to cross the transparent walls. With my performance living between two walls and avoiding any communication with visitors, I expose my private spectacle to the visitors, giving them the sense of strangeness that I am used to in a public space. Reconstructing and revealing the inside space of our spatial, social, psychological boundaries result in an individual and collective narrative. Thus the transparent boundary as a metaphor of physically constructed psycho-social boundaries, examines my strangeness in a room and realizes the invisible walls in our social landscape.by Jae-Chol Lee.S.M

Design of computational measuring system

Thesis (S.M.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 2001.Includes bibliographical references (p. 85-86).This thesis introduces HandSCAPE, a computational measuring system that provides designers and workers with a fluid means of bridging physical measuring and three dimensional computer modeling. Using embedded orientation awareness and wireless communication, the HandSCAPE system first captures vector measurements using a digitally augmented tape measure, and then displays in real time the resulting dimensions in three dimensional computer graphics. With efficiency of human-scale interaction using a tangible user interface, prototype systems are applied for specific on-site space planning, packing configuration, and archaeological field excavation in order to give users in the field immediate access to computational information. Underlying technology for custom orientation sensing and simulating three-dimensional graphics, as well as a concept of digitally constructed physical space are described. The success of the second generation of the system is also equipped with configurable parameters to increase the usability.by Jae-Chol Lee.S.M

Investigation of Microbial Community Analysis during the Decomposition of Lignocellulosic Biomass Using Rumen Fluid

Poster Sessio

Pretreatment of Lignocellulosic Rapeseed Waste by Rumen Fluid for Methane Production

Poster Sessio

Relation between Obesity and Bone Mineral Density and Vertebral Fractures in Korean Postmenopausal Women

PURPOSE: The traditional belief that obesity is protective against osteoporosis has been questioned. Recent epidemiologic studies show that body fat itself may be a risk factor for osteoporosis and bone fractures. Accumulating evidence suggests that metabolic syndrome and the individual components of metabolic syndrome such as hypertension, increased triglycerides, and reduced high-density lipoprotein cholesterol are also risk factors for low bone mineral density. Using a cross sectional study design, we evaluated the associations between obesity or metabolic syndrome and bone mineral density (BMD) or vertebral fracture. MATERIALS AND METHODS: A total of 907 postmenopausal healthy female subjects, aged 60-79 years, were recruited from woman hospitals in Seoul, South Korea. BMD, vetebral fracture, bone markers, and body composition including body weight, body mass index (BMI), percentage body fat, and waist circumference were measured. RESULTS: After adjusting for age, smoking status, alcohol consumption, total calcium intake, and total energy intake, waist circumference was negatively related to BMD of all sites (lumbar BMD p = 0.037, all sites of femur BMD p < 0.001) whereas body weight was still positively related to BMD of all sites (p < 0.001). Percentage body fat and waist circumference were much higher in the fracture group than the non-fracture group (p = 0.0383, 0.082 respectively). Serum glucose levels were positively correlated to lumbar BMD (p = 0.016), femoral neck BMD (p = 0.0335), and femoral trochanter BMD (p = 0.0082). Serum high density lipoprotein cholesterol (HDLC) was positively related to femoral trochanter BMD (p = 0.0366) and was lower in the control group than the fracture group (p = 0.011). CONCLUSION: In contrast to the effect favorable body weight on bone mineral density, high percentage body fat and waist circumference are related to low BMD and a vertebral fracture. Some components of metabolic syndrome were related to BMD and a vertebral fractureope

Letter of Intent of the Government of Korea

https://www.imf.org/external/np/loi/072498.ht