Assessing the representativeness of wind data for wind turbine site evaluation

Once potential wind turbine sites (either for single installations or clusters) are identified through siting procedures, actual evaluation of the sites must commence. This evaluation is needed to obtain estimates of wind turbine performance and to identify hazards to the machine from the turbulence component of the atmosphere. These estimates allow for more detailed project planning and for preliminary financing arrangements to be secured. The site evaluation process can occur in two stages: (1) utilizing existing nearby data, and (2) establishing and monitoring an onsite measurement program. Since step (2) requires a period of at least 1 yr or more from the time a potential site has been identified, step (1) is often an essential stage in the preliminary evaluation process. Both the methods that have been developed and the unknowns that still exist in assessing the representativeness of available data to a nearby wind turbine site are discussed. How the assessment of the representativeness of available data can be used to develop a more effective onsite meteorological measurement program is also discussed

Does uncertainty make a time-varying natural rate of interest irrelevant for the conduct of monetary policy?

We compute optimized monetary policy rules for the ECB when the euro area economy is described by a small empirical macroeconomic model with a time-varying natural interest rate which is positively correlated with fluctuations in trend output growth. We investigate the consequences of both measurement uncertainty with respect to unobservable variables and uncertainty about key model parameters. An optimized Taylor rule with time-varying neutral rate appears to perform well compared to the unconstrained optimal policy, and better than other simple rules found in the literature, even when it is penalized by taking into account both types of uncertainty.Monetary policy rules ; Natural rate of interest ; Uncertainty.

A Time-Varying Natural Rate for the Euro Area

In this article we estimate a time-varying " natural " rate of interest (TVNRI) for a synthetic euro area over the period 1979Q1-2002Q4 using a small backward-looking macroeconomic model, broadly following a methodology developed by Laubach and Williams (2003) for the United States. The Kalman filter simultaneously estimates two unobservable variables: the output gap and the natural rate of interest. The underlying state-space model incorporates an aggregate demand equation and a Phillips curve. Consistent with the theoretical intuition, our identifying assumptions include a close relationship between the TVNRI and the low-frequency fluctuations of potential output growth. The resulting interest rate gap, that is, the difference between the real rate of interest and its estimated natural level, provides us with a valuable tool for assessing the monetary policy stance in EU12 over the last two decades. While our TVNRI estimate seems quite robust to changes in model specifications, the relatively high uncertainty surrounding the estimate hampers its direct integration into the policy-making process.Natural rate of interest ; Interest rate gap ; Monetary policy ; Kalman filter ; Output gap.

Doppler lidar results from the San Gorgonio Pass experiments

During FY-84, the Doppler Lidar data from the San Gorgonio Pass experiments were analyzed, evaluated, and interpreted with regard to signal strength, signal width, magnitude and direction of velocity component and a goodness parameter associated with the expected noise level of the signal. From these parameters, a screening criteria was developed to eliminate questionable data. For the most part analysis supports the validity of Doppler Lidar data obtained at San Gorgonio Pass with respect to the mean velocity magnitude and direction. The question as to whether the Doppler width could be interpreted as a measure of the variance of the turbulence within the Doppler Lidar System (DLS) focal volume was not resolved. The stochastic nature of the Doppler broadening from finite residence time of the particles in the beam as well as other Doppler broadening phenomenon tend to mask the Doppler spread associated with small scale turbulence. Future tests with longer pulses may assist in better understanding

A study of farm women in Hawkins County, Tennessee regarding their perception of tasks in home, farm, employment, and community activities

The purpose of this study was to gain knowledge concerning farm women in Hawkins County and how they perceived their home, farm, employment, and community responsibilities and activities. Personal characteristics studied included marital status, off-farm employment, age, education, residency, and farm and home activities. Data were obtained from 202 Hawkins County farm women randomly selected from 4,461 names listed by the Agricultural Stabilization Conservation Service as having a farm in Hawkins County. The instrument was developed specifically for this study. Information was secured by telephone interviews. The chi square test, Pearsonian correlation coefficient, Scheffe\u27s Post Hoc analysis. Reliability analysis scale, and Crombach\u27s Alpha coefficients were the statistical tests used to determine strength of relationships between variables. A probability level of .05 was considered as being statistically significant. Major findings included: 1. The largest percentages of surveyed Hawkins County farm women were middle-aged (35 to 54 years old) or older (55 years and over), were employed in off-farm work, had a high school or better education, and had no more than one child living at home. 2. Hawkins County farm women who were employed off the farm were more likely than those not employed off the farm to indicate they did not have adequate time for themselves, their spouses, their family, or to attend or participate in community activities or volunteer programs. 3. Hawkins County farm women 55 years and older were more likely than younger farm women to indicate they had adequate time for them selves and their families. 4. Hawkins County farm women who had a college education were more likely than those with less education to indicate they had less time for their families or themselves. 5. Hawkins County farm women not employed off the farm took more responsibilities than farm women employed off the farm for meal preparation and cleanup, laundry chores, and light housekeeping. Off-farm employed farm women shared more home and farm tasks especially in child related activities such as babysitting and supervisions of children.. 6. The more farm and home activities that Hawkins County farm women were involved in, the lower the number of community and volunteer activities in which they participated. 7. Full-time employed Hawkins County farm women were more interested in receiving time management and retirement planning materials than were farm women who were employed part-time or not employed off the farm. 8. Hawkins County farm women 54 years and younger were more interested in receiving information on family nutrition and diet, time management, financial planning, stress management, parenting skills, and computerizing farm records than were farm women over 55 years old. 9. Full-time employed Hawkins County farm women were more dissatisfied with their lifestyles than were farm women who were employed part-time or not employed off the farm. 10. Hawkins County farm women who were middle-age, 35 to 54 years old, were more dissatisfied with their lifestyles than farm women 34 years and younger and farm women 55 years and older. Implications and recommendations were also included in this study

Analysis of the NASA/MSFC airborne Doppler lidar results from San Gorgonio Pass, California

The NASA/MSFC Airborne Doppler Lidar System was flown in July 1981 aboard the NASA/Ames Convair 990 on the east side of San Gorgonio Pass California, near Palm Springs, to measure and investigate the accelerated atmospheric wind field discharging from the pass. At this region, the maritime layer from the west coast accelerates through the pass and spreads out over the valley floor on the east side of the pass. The experiment was selected in order to study accelerated flow in and at the exit of the canyon. Ground truth wind data taken concurrently with the flight data were available from approximately 12 meteorological towers and 3 tala kites for limited comparison purposes. The experiment provided the first spatial data for ensemble averaging of spatial correlations to compute lateral and longitudinal length scales in the lateral and longitudinal directions for both components, and information on atmospheric flow in this region of interest from wind energy resource considerations

Analysis of the NASA/MSFC Airborne Doppler Lidar results from San Gorgonio Pass, California

Two days during July of 1981 the NASA/MSFC Airborne Doppler Lidar System (ADLS) was flown aboard the NASA/AMES Convair 990 on the east side of San Gorgonio Pass California, near Palm Springs, to measure and investigate the accelerated atmospheric wind field discharging from the pass. The vertical and horizontal extent of the fast moving atmospheric flow discharging from the San Gorgonio Pass were examined. Conventional ground measurements were also taken during the tests to assist in validating the ADLS results. This particular region is recognized as a high wind resource region and, as such, a knowledge of the horizontal and vertical extent of this flow was of interest for wind energy applications. The statistics of the atmospheric flow field itself as it discharges from the pass and then spreads out over the desert were also of scientific interests. This data provided the first spatial data for ensemble averaging of spatial correlations to compute longitudinal and lateral integral length scales in the longitudinal and lateral directions for both components

Règle de Taylor et politique monétaire dans la zone euro

We estimate the reaction function of monetary policy in the Euro area and derive the Taylor-type policy rule that a would-be ECB would have followed since the beginning of the European Monetary System (1979-2003). We first follow the standard GMM methodology developed by Clarida, Galí and Gertler (1998) under the statistically valid assumption of a stationary data set. A detailed robustness analysis is conducted, in order to assess how the estimation results are affected by changes in the period under review, the set of instruments and the way the output gap is computed. Using the Kalman filter, we estimate in particular a measure of the output gap that is consistent with a small macroeconomic model, which constitutes a novelty of our approach. Secondly, we re-estimate the historical interest rate rule under the assumption of non-stationary data over the 1985-2003 period, following a methodology recently proposed by Gerlach-Kristen (2003). These empirical investigations lead to a reasonably robust descriptive tool of the systematic element in the monetary policy that prevailed on average in the "Euro area" over the last two decades.Kalman filter ; Monetary policy ; Taylor rule ; Euro area.

Stability and dynamic processes in the formation of high plains hailstorms

February, 1969.Includes bibliographical references.Sponsored by the National Science Foundation GA-1561

Explicit Evidence Systems with Common Knowledge

Justification logics are epistemic logics that explicitly include justifications for the agents' knowledge. We develop a multi-agent justification logic with evidence terms for individual agents as well as for common knowledge. We define a Kripke-style semantics that is similar to Fitting's semantics for the Logic of Proofs LP. We show the soundness, completeness, and finite model property of our multi-agent justification logic with respect to this Kripke-style semantics. We demonstrate that our logic is a conservative extension of Yavorskaya's minimal bimodal explicit evidence logic, which is a two-agent version of LP. We discuss the relationship of our logic to the multi-agent modal logic S4 with common knowledge. Finally, we give a brief analysis of the coordinated attack problem in the newly developed language of our logic