Estimating Germany's Potential Output

Potential output measures a country's attainable aggregate living standard and is thus one of the most important categories of economics. It is also a key indicator for monetary and fiscal policy. Despite its prominence, however, potential output is a difficult concept to pinpoint both theoretically and even more so empirically. The article discusses the reasons for the marked revisions of potential output estimates by major international organisations. The authors then present the results of our attempts to quantify Germany's potential output based on a production function approach coupled with the Kalman-filter technique to estimate the NAIRU. The authors find that potential output and potential output growth greatly depend on how the NAIRU and potential total factor productivity are modelled. Given the difficulties involved in robustly estimating potential output, especially in real time, economic policy makers need to learn to pursue their policy objectives without reference to this variable.Potential Output, Nairu, Kalman-filter, revisions

Statistic Approach Based on “Monte-Carlo Simulation” to Calculate Inspection Reliability for Multiple Site Damage

Changes in aircraft design concepts in recent years from “Safe-Life / Fail-Safe” to “Damage-Tolerance” have significantly increased the importance of the role of Nondestructive Inspections (NDI) and have placed a far greater importance on the effectiveness of NDI techniques and their ability to detect defects. To calculate inspection reliabilities based on probability of detection (POD) of the inspection method and “Multiple Site Damage” (MSD) (or “Widespread Fatigue Damage”) assumptions for the defects, an approach to use a “Monte-Carlo Simulation” is described and results for crack inspection of aircraft lap joints are presented

Statistic Approach Based on “Monte-Carlo Simulation” to Calculate Inspection Reliability for Multiple Site Damage

Changes in aircraft design concepts in recent years from “Safe-Life / Fail-Safe” to “Damage-Tolerance” have significantly increased the importance of the role of Nondestructive Inspections (NDI) and have placed a far greater importance on the effectiveness of NDI techniques and their ability to detect defects. To calculate inspection reliabilities based on probability of detection (POD) of the inspection method and “Multiple Site Damage” (MSD) (or “Widespread Fatigue Damage”) assumptions for the defects, an approach to use a “Monte-Carlo Simulation” is described and results for crack inspection of aircraft lap joints are presented.</p

Phase Stepping Shearography for Testing Commercial Aircraft Structures: An Application Review of Advanced Image Processing Techniques for Shearography

Interferometric NDT methods have a long history in the laboratories of DAIMLER BENZ AEROSPACE Airbus, even first papers about early approaches to shearography go back into the late seventies, when in the Lemwerder Labs of former VFW-Fokker the first shearography setup was assembled [1]. That time using film or thermoplast camera the method proved to be too complicated for in field applications. During the following years the acceptance of interferometric NDT methods remained poor as the typical test results were represented by complex fringe patterns. These patterns could be interpreted only by well trained specialists. It was sometimes impossible to extract the defect information from complex fringe patterns caused by the geometry of the test specimen. In the spectrum of different approaches to overcome this problem the phase stepping fringe analysis method showed great potential in conjunction with the capabilities of shearography.</p