Understanding the postwar decline in United States saving: a cohort analysis

An analysis of the postwar decline in U.S. national saving that decomposes changes in the net national saving rate into those due to changes in cohort-specific consumption propensities, the intergenerational distribution of resources, the rate of government spending, and demographics. ; A review and expansion of Calomiris, Kahn, and Longhofer's (1994) cultural affinity theory of discrimination in the residential mortgage market, which is based on the idea that lenders find it easier or less costly to evaluate the creditworthiness of applicants with whom they have a common experiential background.Saving and investment

The Flight Telerobotic Servicer (FTS) NASA's first operational robotic system

NASA has completed the preliminary definition phase of the Flight Telerobotic Servicer (FTS) and is now preparing to begin the detailed design and fabrication phase. The FTS will be designed and built by Martin Marietta Astronautics Group in Denver, CO, for the Goddard Space Flight Center, in support of the Space Station Freedom Program. The design concepts for the FTS are discussed, as well as operational scenarios for the assembly, maintenance, servicing and inspection tasks which are being considered for the FTS. The upcoming Development Test Flight (DTF-1) is the first of two shuttle test flights to test FTS operations in the environment of space and to demonstrate the FTS capabilities in performing tasks for Space Station Freedom. Operational planning for DTF-1 is discussed as well as development plans for the operational support of the FTS on the space station

The annuitization of Americans' resources: a cohort analysis

An analysis of the changes since 1960 in the share of Americans' resources that are annuitized, which has declined slightly for younger Americans but has risen dramatically for the elderly, with important implications for the national saving rate and income inequality.Saving and investment

Safe Supervisory Control of Soft Robot Actuators

Although soft robots show safer interactions with their environment than traditional robots, soft mechanisms and actuators still have significant potential for damage or degradation particularly during unmodeled contact. This article introduces a feedback strategy for safe soft actuator operation during control of a soft robot. To do so, a supervisory controller monitors actuator state and dynamically saturates control inputs to avoid conditions that could lead to physical damage. We prove that, under certain conditions, the supervisory controller is stable and verifiably safe. We then demonstrate completely onboard operation of the supervisory controller using a soft thermally-actuated robot limb with embedded shape memory alloy (SMA) actuators and sensing. Tests performed with the supervisor verify its theoretical properties and show stabilization of the robot limb's pose in free space. Finally, experiments show that our approach prevents overheating during contact (including environmental constraints and human contact) or when infeasible motions are commanded. This supervisory controller, and its ability to be executed with completely onboard sensing, has the potential to make soft robot actuators reliable enough for practical use

The Annuitization of Americans' Resources: A Cohort Analysis

This paper constructs a unique cohort data set to study the changes since 1960 in the share of Americans' resources that are annuitized. Understanding these changes is important because the larger this share, the more cohorts are likely to consume and the less they are likely to bequeath. Hence, the degree of annuitization affects national saving as well as the transmission of inequality over time. Our findings are striking. Although the annuitized share of resources of younger Americans declined slightly between 1960 and 1990, it increased dramatically for older Americans. It doubled for older men and quadrupled for older women. Since the elderly have much higher mortality probabilities than do the young, their degree of annuitization is much more important for aggregate bequests and saving. According to our estimates, aggregate U.S. bequests would now be 66 percent larger had the post-1960 increase in annuitization not occurred. In addition, U.S. national saving would likely be substantially larger than is currently the case.

Understanding the Postwar Decline in U.S. Saving: A Cohort Analysis

Since 1980, the U.S. net national saving rate has averaged less than half the rate observed in the 1950s and 60s. This paper develops a unique cohort data set to study the decline in U.S. national saving. It decomposes postwar changes in U.S. saving into those due to changes in cohort-specific consumption propensities, those due to changes in the intergenerational distribution of resources, those due to changes in government spending on goods and services, and those due to changes in demographics. Our findings are striking. The decline in U.S. saving can be traced to two factors: The redistribution of resources from young and unborn generations with low or zero propensities to consume toward older generations with high consumption propensities, and a significant increase in the consumption propensities of older Americans. Most of the redistribution to the elderly reflects the growth in Social Security, Medicare, and Medicaid benefits. The increase in the elderly's consumption propensities may also reflect government policy, namely the fact that Social Security, Medicare, and Medicaid benefits are paid in the form of annuities and that, in the case of Medicare and Medicaid, the annuities are in-kind and must, therefore, be consumed.

Landsat-7 Simulation and Testing Environments

A spacecraft Attitude Control and Determination Subsystem (ACDS) is heavily dependent upon simulation throughout its entire development, implementation and ground test cycle. Engineering simulation tools are typically developed to design and analyze control systems to validate the design and software simulation tools are required to qualify the flight software. However, the need for simulation does not end here. Operating the ACDS of a spacecraft on the ground requires the simulation of spacecraft dynamics, disturbance modeling and celestial body motion. Sensor data must also be simulated and substituted for actual sensor data on the ground so that the spacecraft will respond by sending commands to the actuators as they will on orbit. And finally, the simulators is the primary training tool and test-bed for the Flight Operations Team. In this paper various ACDS simulation, developed for or used by the Landsat 7 project will be described. The paper will include a description of each tool, its unique attributes, and its role in the overall development and testing of the ACDS. Finally, a section is included which discusses how the coordinated use of these simulation tools can maximize the probability of uncovering software, hardware and operations errors during the ground test process