Search

A study was conducted to examine the risk facing a well-documented and important class of entrepreneurs, those supported by venture capital. Findings indicate that the payoff to a venture-backed entrepreneur comprises a below-market salary and a share of the equity value of the company when it goes public.

How mortgage market works in order to justify regulatory intervention is presented. The relationship of the charges on mortgages to borrower characteristics and loan details is described using lender data and Federal Housing Administration loans on complete mortgage costs to borrowers. How these charges differ by the major types of originators is also discussed.

The Economic Fluctuations and Growth (EF&G) Program goes back to the beginning of Martin Feldstein's presidency of the NBER, although originally it was simply called the Economic Fluctuations Program. It [...]

A study was conducted to examine a noncooperative alternating offer model that improves two common conceptions of wage bargaining. One conception states that employers set wages and other terms and hire the most qualified applicant willing to work on those terms, while the other conception assumes that the threat point for bargaining is a payoff pair.

Using a model based on standard economic assumptions, the reasons for the increase in health care expenditure in recent times, are studied.

The free-to-roll technique is used as a tool for predicting areas of uncommanded lateral motions. Recently, the NASA/Navy/Air Force Abrupt Wing Stall Program extended the use of this technique to the transonic speed regime. Using this technique, this paper evaluates various wing configurations on the Joint Strike Fighter (F-35) aircraft. The configurations investigated include leading- and trailing-edge flap deflections, leading-edge flap gap seals, and vortex generators. These tests were conducted in the NASA Langley 16-Foot Transonic Tunnel. The analysis used a modification of a figure of merit developed during the Abrupt Wing Stall Program to discern configuration effects. The results showed how the figure of merit can be used to schedule wing flap deflections to avoid areas of uncommanded lateral motion. The analysis also used both static and dynamic wind-tunnel data to provide insight into the uncommanded lateral behavior. The dynamic data were extracted from the time history data using parameter identification techniques. In general, sealing the gap between the inboard and outboard leading-edge flaps on the Navy version of the F-35 eliminated uncommanded lateral activity or delayed the activity to a higher angle of attack.

The reviews of the 2005 Economic Report of the President (ERP) are analyzed in detail to provide an assessment of the consensus professional views of economists.

The Abrupt-Wing-Stall (AWS) Program has addressed the problem of uncommanded lateral motions, such as wing drop and wing rock, at transonic speeds. The genesis of this program was the experience of the F/A-18E/F program in the late 1990s, when wing drop was discovered in the heart of the maneuver envelope for the preproduction aircraft. Although the F/A-18E/F problem was subsequently corrected by a leading-edge flap scheduling change and the addition of a porous door to the wing fold fairing, the AWS program was initiated as a national response to the lack of technology readiness at the time of the F/A-18E/F development program. The AWS program objectives were to define causal factors for the F/A-18E/F experience, to gain insights into the flow physics associated with wing drop, and to develop methods and analytical tools so that future programs could identify this type of problem before going to flight test. The major goals of the AWS Program, the status of the technology before the program began, the program objectives, the accomplishments, and the impacts are reviewed. Lessons learned are presented for the benefit of programs that must assess whether a future vehicle will have uncommanded lateral motions before going to flight test.

A transonic wind-tunnel test of an 8% F/A-18E model was conducted in the NASA Langley Research Center 16 ft Transonic Tunnel to investigate on-surface flow physics during stall. The technical approach employed focused on correlating static (or time-averaged) and unsteady wind-tunnel test data to the unsteady wing-stall events using force, moment, pressure, and pressure-sensitive-paint measurements. This paper focuses on data obtained on the preproduction configuration of the F/A-18E aircraft at Math number of 0.90. The flow unsteadiness occurring on the wing as the wing went through the stall process was captured using the time histories of balance and pressure measurements and by calculating the root mean square (rms) for a number of instrument signals. The second step was to gather global perspectives on the pressures influencing the wing-stall process. The abrupt wing stall experienced by the 8% F/A-18E model was observed to be an unsteady event triggered by the rapid advancement of separation, which had migrated forward from the trailing edge, to the leading-edge flap hingeline over a very small increment in angle of attack. The angle of attack at which this stall occurred varied, from run to run, over a 1-deg increment. The abrupt wing stall was observed, using pressure-sensitive paint, to occur simultaneously on both wing panels or asymmetrically. The pressure-sensitive-paint data and wing-root bending-moment data were essential in providing insight to the flow structures occurring over the wing and the possible asymmetry of those flow structures. A repeatability analysis conducted on eight runs of static data provided a quick and inexpensive examination of the unsteady aerodynamic characteristics of abrupt wing stall. The results of the repeatability analysis agreed extremely well with data obtained using unsteady measurement techniques. This approach could be used to identify test conditions for more complex unsteady data measurements using special instrumentation.

The effect of recession on labor markets and wages is examined. A model analyzing the correlation between employment and wages during the recession period is also presented.

Adjustment costs for labor and capital are measured using standard econometric methods on factor-adjustment Euler equations. It is identified that labor and capital have low adjustment costs and that they do not appear to be held back by significant adjustment costs.

The Abrupt Wing Stall (AWS) Program has addressed the problem of uncommanded, transonic lateral motions, such as wing drop, with experimental, computational, and simulation tools. Background to the establishment of the AWS program is given as well as program objectives. To understand the fundamental flow mechanisms that caused the undesirable motions for a preproduction version of the F/A-18E, steady and unsteady flowfield details were gathered from dedicated transonic wind-tunnel testing and computational studies. The AWS program has also adapted a free-to-roll (FTR) wind-tunnel testing technique traditionally used for low-speed studies of lateral dynamic stability to the transonic flow regime. This FTR capability was demonstrated first in a proof-of-concept study and then applied to an assessment of four different aircraft configurations. Figures of merit for static testing and for FTR testing have been evaluated for two configurations that demonstrated wing-drop susceptibility during full-scale flight conditions (the preproduction F/A-18E and the AV-8B at the extremes of its flight envelope) and two configurations that do not exhibit wing drop (the F/A-18C and the F-16C). Design insights have been obtained from aerodynamic computational studies of the four aircraft configurations and from computations quantifying the impact of the various geometric wing differences between the F/A-18C and the F/A-18E wings. Finally, the AWS program provides guidance for assessing, in the simulator, the impact of experimentally determined lateral activity on flight characteristics before going to flight.

A review of the experimental program for four different aircraft configurations conducted as part of the Abrupt Wing Stall Program has been made. Several candidate figures of merit from conventional static-tunnel tests are summarized and correlated with data obtained in unique free-to-roll tests. The conclusion from this study is that these figures of merit can by themselves give some indication as to whether an aircraft would experience uncommanded lateral activity caused by abrupt wing stall. However, no one specific figure of merit consistently flagged a warning of potential lateral activity when actual activity was seen to occur in the free-to-roll experiments. In fact, they yielded as many or more false indications of lateral activity then were seen in the free-to-roll response data. Excellent agreement between free-to-roll results and flight was obtained for those configurations where flight data were available.

An approach is provided to answer the question of whether one can rely solely on static data taken during a transonic model test to provide the certainty needed that a new aircraft will or will not have abrupt wing stall (AWS) events during its flight operations. By the comparison of traditional static figures of merit (FOMs) with the free-to-roll (FTR) response data, a rational basis for assessing the merits of using standard testing techniques for the prediction of AWS events has been established. With use of the FTR response data as a standard, because these results compare well with flight, it is concluded that traditional FOMs can not be trusted to provide an indication as to whether a configuration will or will not have AWS tendencies. Even though these FOMs may flag features that have a high degree of correlation with the FTR response data, there are as many or more of these FOM flagged features that do not correlate. Thus, one needs to use the FTR rig to assess AWS tendencies on new configurations.

Transonic free-to-roll and static wind-tunnel tests for four military aircraft--the AV-8B, the F/A-18C, the preproduction F/A-18E, and the F-16C--have been analyzed. These tests were conducted in the NASA Langley 16-Foot Transonic Tunnel as a part of the NASA/Navy/Air Force Abrupt Wing Stall Program. The objectives were to evaluate the utility of the free-to-roll test technique as a tool for predicting areas of significant uncommanded lateral motions and for gaining insight into the wing-drop and wing-rock behavior of military aircraft at transonic conditions. The analysis indicated that the free-to-roll results agreed well with flight data on all four models. A wide range of motions--limit-cycle wing rock, occasional and frequent damped wing drop/rock and wing-rock divergence--were observed. The analysis shows the effects that static and dynamic lateral stability can have on the wing-drop/rock behavior. In addition, a free-to-roll figure of merit was developed to assist in the interpretation of results and assessment of the severity of the motions.

As part of the NASA/Navy Abrupt Wing Stall Program, a relatively low-cost, rapid-access, free-to-roll test rig was developed on which conventional high-strength wind-tunnel models can be used to evaluate both transonic performance and wing-drop/rock behavior in a single tunnel entry. The overall objective was to demonstrate the utility of the free-to-roll test technique as a tool for identifying areas of significant uncommanded lateral activity during ground testing and for gaining insight into the wing-drop/rock behavior of military aircraft at transonic conditions. A description of the test hardware as well as a description of the experimental procedures is given. The free-to-roll test rig has been used successfully to assess the static and dynamic characteristics of four different configurations--two configurations that exhibited uncommanded lateral motions inflight (preproduction F/A-18E and AV-8B) and two that did not (F/A-18C, F-16C). Excellent agreement between free-to-roll results and flight was obtained for those configurations where flight data were available.

This paper presents the results of a survey of past experiences with uncommanded lateral-directional motions at transonic speeds during specific military aircraft programs. The effort was undertaken to provide qualitative and quantitative information on past airplane programs that might be of use to the participants in the joint NASA/Navy/Air Force Abrupt Wing Stall Program. The Abrupt Wing Stall (AWS) Program was initiated because of the experiences of the F/A-18E/F development program, during which unexpected, severe wing-drop motions were encountered by preproduction aircraft at transonic conditions. These motions were judged to be significantly degrading to the primary mission requirements of the aircraft. Although the problem was subsequently solved for the production version of the F/A-18E/F, a high-level review panel emphasized the poor understanding of such phenomena and issued a strong recommendation to 'initiate a national research effort to thoroughly and systematically study the wing drop phenomena.' A comprehensive, cooperative NASA/Navy/Air Force AWS Program was designed to respond to provide the required technology requirements. A work element was directed at a historical review of wing-drop experiences in past aircraft development programs at high subsonic and transonic speeds. In particular, information was requested regarding: specific aircraft configurations that exhibited uncommanded motions and the nature of the motions; geometric characteristics of the airplanes; flight conditions involved in occurrences; relevant data, including wind-tunnel, computational, and flight sources; figures of merit used for analyses; and approaches used to alleviate the problem. An attempt was also made to summarize some of the more important lessons learned from past experiences and to recommend specific research efforts.

The NBER's Research Program on Economic Fluctuations and Growth marks its 25th anniversary this year. During the long U.S. economic expansion of the 1990s--the longest in the chronology maintained by [...]

Understanding the variations in the natural rate of employment over time is critical for economic policy making. Policy makers have adopted the view that the natural rate varies over time and it is not a simple benchmark for setting monetary instruments.

The value of a firm's securities measures the value of the firm's productive assets. If the assets include only capital goods and not a permanent monopoly franchise, the value of the securities measures the value of the capital. Finally, if the price of the capital can be measured or inferred, the quantity of capital is the value divided by the price. A standard model of adjustment costs enables the inference of the price of installed capital. Data from U.S. corporations over the past 50 years imply that corporations have formed large amounts of intangible capital, especially in the past decade. (JEL E44, G12), The value of a firm's securities measures the value of the firm's productive assets. If the assets include only capital goods and not a permanent monopoly franchise, the value of the securities measures the value of the capital. Finally, if the price of the capital can be measured or inferred, the quantity of capital is the value divided by the price. A standard model of adjustment costs enables the inference of the price of installed capital. Data from U.S. corporations over the past 50 years imply that corporations have formed large amounts of intangible capital, especially in the past decade. (JEL E44, G12)

An economist tries to understand the behavior of the stock market by studying how stocks values are derived. He believes that stock market movements are not random, but are controlled by rational economic decisions made by investors.

The effects of Microsoft's challenged conduct are quantified, and policies designed to control artificial barriers are examined.

Empirical research on economic growth is used to examine the levels of economic development across countries. The study makes good use of available data and concentrates on the level of output per worker. The variations in the levels of economic growth across countries are influenced by government policies or infrastructure. These create the economic environment where people work, transact, learn skills and invent. Countries that support production through solid physical and intellectual property rights are successful.

The adoption of a consumption tax may result in possible disruptions. Price levels and the after-tax interest rate may increase while value of housing may decrease. Compared with consumption goods, the value of capital goods may decrease because of a decrease in tax. Such disruptions must be considered in the design of tax reform proposals. While other disruptions are innate to consumption tax, a sensible design can eliminate some disruptions.

What are the fundamental driving forces of macroeconomic fluctuations? In particular, why do people spend more time working in booms and less in recessions? These are basic questions of macroeconomics. Recent thinking has emphasized technology shifts, preference shifts, and changes in government purchases as likely driving forces. It is useful to distinguish atemporal and intertemporal effects of the driving forces. Under standard assumptions, the technology shift has no effect through atemporal channels because income and substitution effects exactly offset. A straightforward decomposition of movements of employment attributes most of them to the atemporal effects of preference shifts.

The National Bureau of Economic research project on economic fluctuations and growth is handled by small groups under the leadership of Princeton University's Ben S. Bernanke and Massachusetts Institute of Technology's Julio J. Rotemberg. Research focused on human capital development, capital market inequality and how income distribution influences growth and macroeconomic activity. Studies were also conducted on the sources and consequences of economic fluctuations, labor markets, monetary demand and government policy., The U.S. economy has enjoyed uninterrupted growth since the trough of the last recession in the spring of 1991. As unemployment has declined to just over 5 percent, attention has [...]

Availability of public capital contributes to the variation in average labor productivity across the US. Density, or the concentration of capital within a given space, is high when there is huge amount of labor and capital in a physical space. An increase in density also gives rise to an increase in returns. It was further determined that when employment density is doubled, the average labor productivity of a county increases by 6%.

design seems to be spontaneously occurring in Russia. But far and away the most important core investors have been the people who have made a lot of money during the [...]

The National Bureau of Economic Research (NBER) is focusing on US economic conditions in its Program on Economic Fluctuations. The American business cycle is categorized according to its sources, propagation mechanisms and policy effects. The NBER program has established groups which will focus on specific aspects of the cycle. A cycle chronology will also be part of the bureau's research on economic developments in the country., The U.S. business cycle continues to be the main concern of the NBER's Program on Economic Fluctuations. We have examined the sources of the business cycle, propagation mechanisms, and policy [...]

Eight possible causes for the recession are considered within the context of macro theories, and established models prove to be ineffective in an analysis of the recession. The recession seems largely a result of an array of negative responses that followed the invasion of Kuwait by Iraq and the consequent rise in oil prices in Aug 1990. Consumers responded as they would to a decrease in resources.

Advanced control room designs were evaluated with respect to their relationship to crew performance. Results of the evaluation show that despite the fact that ACR technology can potentially improve system performance, it can also create a negative impact on human performance and create opportunities for human errors. The lack of knowledge about the role of human operators on human performance, available databases and subject matter expertise were found to contribute to the inability of adequately evaluating human functioning in advanced control rooms.

Economic Fluctuations Robert E. Hall The research activities of the NBER's Program on Economic Fluctuations are arranged through a number of small working groups as well as in individual projects. [...]

Techniques for achieving increased efficiency in thin-film polycrystalline silicon solar cells are presented, using an insulating ceramic substrate to produce back surface passivation and light trapping.

Output per worker varies enormously across countries. Why? On an accounting basis our analysis shows that differences in physical capital and educational attainment can only partially explain the variation in output per worker - we find a large amount of variation in the level of the Solow residual across countries. At a deeper level, we document that the differences in capital accumulation, productivity, and therefore output per worker are driven by differences in institutions and government policies, which we call social infrastructure. We treat social infrastructure as endogenous, determined historically by location and other factors captured in part by language., I. INTRODUCTION In 1988 output per worker in the United States was more than 35 times higher than output per worker in Niger. In just over ten days the average [...]

By Michael Huberman New York: Cambridge University Press, 1997. xvii + 222 pp. Tables, figures, glossary, notes, bibliography, and index. $54.95. ISBN 0-521-56151-5. Reviewed by Robert Hall This book analyzes [...]