Development of an interface for an ultrareliable fault-tolerant control system and an electronic servo-control unit

The NASA Ames Research Center sponsors a research program for the investigation of Intelligent Flight Control Actuation systems. The use of artificial intelligence techniques in conjunction with algorithmic techniques for autonomous, decentralized fault management of flight-control actuation systems is explored under this program. The design, development, and operation of the interface for laboratory investigation of this program is documented. The interface, architecturally based on the Intel 8751 microcontroller, is an interrupt-driven system designed to receive a digital message from an ultrareliable fault-tolerant control system (UFTCS). The interface links the UFTCS to an electronic servo-control unit, which controls a set of hydraulic actuators. It was necessary to build a UFTCS emulator (also based on the Intel 8751) to provide signal sources for testing the equipment

A Tariff-Growth Paradox? Protection's Impact the World Around 1875-1997

This paper uses a new database to establish two findings covering the first globalization boom before World War I, the second since World War II, and the autarkic interlude in between. First, there is strong evidence supporting a Tariff-Growth Paradox: protection was associated with fast growth before World War II, while it was associated with slow growth thereafter. Second, there is strong evidence supporting regional asymmetry: while the tariff-growth association was powerful and positive in the Core and rich New World before World War II, it was typically weak and negative in the poor Periphery. The paper offers explanations for the Paradox by controlling for a changing world economic environment. It shows how the oft-quoted Sachs-Warner results for 1970-1989 are significantly revised when one controls for trading partners' growth, trading partners' tariffs and the effective distance between them over the longer half-century 1950-1997. Falling partners' tariffs was the most important force accounting for the switch in sign on the tariff-growth connection after 1950. An increase in own tariffs after 1950 hurt growth, but it would not have hurt growth in a world where partners' tariffs were much higher, trading partners' growth much slower, and the world less closely connected by transportation. World environment matters. Leader-country reaction to big world events (like the Great Depression) matter. Followers take notice.

Where did British Foreign Capital Go? Fundamentals, Failures and the Lucas Paradox: 1870-1913

A decade has passed since Robert Lucas asked why capital does not flow from rich to poor countries. Lucas used a contemporary example to illustrate his Paradox, the very modest flow of capital from the United States to India during the second great global capital market boom, after 1970. Had he paid more attention to the first great global capital market boom, after 1870, he might have been less surprised. Very little of British capital exports went to poor, labor-abundant countries. Indeed, about two-thirds of it went to the labor-scarce New World where only a tenth of the world's population lived, and only about a quarter of it went to labor-abundant Asia and Africa where almost two-thirds of the world's population lived. Why? Was it caused by some international market failure, or was it due to some shortfall in underlying economic, demographic or geographic fundamentals that made capital's productivity low in poor countries? This paper constructs a panel data set for 34 countries who as a group got 92 percent of British capital, and uses it to conclude that international capital market failure (including whether the country was on or off the Gold Standard) was not involved. It then ranks the three big fundamentals that mattered schooling, natural resources and demography.

Closed Jaguar, Open Dragon: Comparing Tariffs in Latin America and Asia before World War II

Despite an enormous literature that has analyzed the comparative experiences of Latin America and Asia in post-World War II trade policy, almost no attention has been paid to the comparative experience prior to the wars. Even a cursory look at the best available empirical evidence reveals tremendous contrasts between the two regions. Latin America had the highest tariff barriers on earth before 1914; Asia had the lowest. Protected Latin America's belle ‚poque also boasted some of the most explosive growth performance on earth, while Asia registered some of the worst. What brought the two regions to the opposite ends of the tariff policy spectrum? And why are these quantum differences in economic performance so at odds with postwar conventional wisdom? We begin by describing a novel tariff database we have constructed from largely original sources. We explore the impact of colonial rule and unequal treaties' on Asian tariffs, as well as the impact of geography and political economy on Latin American tariffs. Limits to tariff policy autonomy explain one third of the vast difference between the two regions' tariffs before 1914; differences in the extent and structure of internal markets as well as the world tariff environment explain much of the rest. We conclude with an agenda for the future.

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. III. HD 82191, Omega Draconis, And 108 Herculis

We have determined improved spectroscopic orbits for three double-lined binaries, HD 82191 (Am), omega Dra (F5 V), and 108 Her (Am), using radial velocities from the 2.1 m telescope at McDonald Observatory, the coude feed telescope at Kitt Peak National Observatory, and 2 m telescope at Fairborn Observatory. The orbital periods range from 5.28 to 9.01 days, and all three systems have circular orbits. The new orbital dimensions (a(1) sin i and a(2) sin i) and minimum masses (m(1) sin(3) i and m(2) sin(3) i) have accuracies of 0.2% or better. Our improved results confirm the large minimum masses of HD 82191 and also agree with the values previously found for. Dra. However, for the components of 108 Her our minimum masses are about 20% larger than the previous best values. We conclude that both components of HD 82191 as well as the primary of 108 Her are Am stars. However, the A9 secondary of 108 Her has normal abundances. We estimate spectral types of F4 dwarf and G0 dwarf for the components of. Dra. The primaries of the three binaries are synchronously rotating as is the secondary of 108 Her. The secondaries of HD 82191 and omega Dra are possibly synchronously rotating.NASA NCC5-511NSF HRD-9706268Astronom

New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. VIII. HR 1528, HR 6993, 2 Sagittae, And 18 Vulpeculae

Improved orbital elements for four A-star double-lined spectroscopic binaries have been determined with numerous new radial velocities. Three of the four systems, HR 1528, 2 Sge, and 18 Vul, have moderately short orbital periods of 7.05, 7.39, and 9.31 days, respectively, and also have circular or nearly circular orbits. Only HR 6993 with a period of 14.68 days has a significantly eccentric orbit. The close visual companion of 2 Sge has been detected spectroscopically, and its velocity measured. The orbital dimensions (a(1) sin i and a(2) sin i) and minimum masses (m(1) sin(3) i and m(2) sin(3) i) of the short-period binary components all have accuracies of 0.5% or better. We determine basic properties of the individual stars and compare them with solar-abundance evolutionary tracks to estimate their masses. Half of the eight components may be synchronously or pseudosynchronously rotating.NASANSFTennessee State UniversityState of Tennessee through its Centers of ExcellenceAstronom