67 research outputs found
Anticipation, learning and welfare: the case of distortionary taxation
We study the impact of anticipated fiscal policy changes in the Ramsey economy when agents form expectations using adaptive learning. We extend the existing framework by distortionary taxes as well as elastic labour supply, which makes agents' decisions non-predetermined but more realistic. We detect that the dynamic responses to anticipated tax changes under learning have oscillatory behaviour. Moreover, we demonstrate that this behaviour can have important implications for the welfare consequences of fiscal reforms.Fiscal Policy; Adaptive Learning; Oscillations
Essay on public policy evaluations and labour market
In der Dissertation werden makroökonomische Modelle mit Arbeitsmarktsbeschränkung verwendet, um einige Public Policies zu evaluieren.
In dem ersten Modell werden Job Creation und Job Destruction in Anwesenheit von sowohl Search Friction als auch Unternehmensheterogenität im Arbeitsmarkt und Gütermarkt untersucht. Es wird gezeigt, dass nicht nur die Arbeitslosenquote sondern auch die Rate der endogenen Job Creation ansteigen, wenn die Inflationsrate zunimmt. Die numerischen Ergebnisse zeigen, dass die Zerstörung der Arbeitsplätze von geringerer Produktivität und die Schaffung der Arbeitsplätze von höherer Produktivität unter der Friedman Rule wirkungslos niedrig sein können. Das führt darüber hinaus die Deviation der optimalen Geldpolitik in der langen Frist herbei.
In dem zweiten Modell werden der Effekt der Inflation auf Lohnspreizung aufgrund der Unternehmensheterogenität und on-the-job Search im Rahmen eines Arbeitsmarktes à la Postel-Vinay und Robin (International Economic Review 43, 2002) und der mikrofundierten Geldnachfrage untersucht. Die Produktivität (Distribution) der Firmen ist zunächst als exogen angenommen. Es wird gefunden, dass ein Anstieg der Inflation die Lohnspreizung vermindert. Lassen danach die Firmen ihres Produktivitätsniveau durch Investition anpassen, macht ein Anstieg der Inflation zuerst die Produktivitätsniveau der Firmen weniger dispergiert (verteilt); weiterhin vermindert es auch die Lohnspreizung.
In dem dritten Modell wird die Auswirkung der Veränderungen der antizipierten Fiskalpolitik im Rahmen einer Ramsey Ökonomie analysiert, wo Agenten Erwartungen über durchschnittlichen Lohn und Zinssatz durch adaptives Lernen bilden. Der bestehende Rahmen wird mit verzerrenden Steuern und elastisches Arbeitsangebot erweitert, was die Entscheidungen der Agenten nicht vorher determiniert, sondern realistisch macht. Es wird festgestellt, dass die dynamischen Reaktionen auf antizipierte Veränderungen der Steuern unter Lernen einen oszillatorischen Charakter haben. Des Weiteren wird es demonstriert, dass dieser Charakter Wohlfahrtsauswirkung für Fiskalreform haben kann
Anticipation, learning and welfare: the case of distortionary taxation
We study the impact of anticipated fiscal policy changes in the Ramsey economy when agents form expectations using adaptive learning. We extend the existing framework by distortionary taxes as well as elastic labour supply, which makes agents' decisions non-predetermined but more realistic. We detect that the dynamic responses to anticipated tax changes under learning have oscillatory behaviour. Moreover, we demonstrate that this behaviour can have important implications for the welfare consequences of fiscal reforms
Evaluating the Efficiency of Industrialization Process in Prefabricated Residential Buildings Using a Fuzzy Multicriteria Decision-Making Method
To alleviate the housing pressure and achieve a sustainable society, prefabricated residential building (PRB) has witnessed rapid growth in recent years. The usage of prefabricated components in the building represents a significant indicator that is traditionally used to differentiate the PRB from the traditional building. However, it cannot provide details on the efficiency of the industrialization process in the PRB. The main goal of this paper is to develop a composite index to measure the multidimensional concept of industrialization efficiency. Fuzzy Analytic Hierarchy Process (fuzzy AHP) and fuzzy Technique for Order Preference by Similarity to Ideal Solution (fuzzy TOPSIS) are applied to combine the hierarchical structure of indicators into one overall index. Finally, the industrialization efficiency assessment of three PRBs is chosen as a case to illustrate the effectiveness of the method. It can effectively quantify experts’ linguistic expressions on the performance of the PRB in different established indicators. This research can provide a decision support tool to assess and continuously promote the improvement of industrialization production in the housing industry
Experimental study on shear mechanical properties and damage evolution ofartificial structural plane under constant normal stiffness
To study the influence of asperity angle and normal stiffness on the shear mechanical properties of the structural plane, a direct shear test of the artificial structural plane with constant normal stiffness (CNS) was carried out using the self-developed coal rock shear seepage coupling test system. The results show that the shear stress presents a periodic oscillation attenuation trend when the asperity angles are 15° and 30°. At the end of shearing, the reduction in peak shear stress with the increase of normal stiffness is 1.78, 1.42, 1.36 and 1.27 MPa, respectively, which is gradually decreasing. While the asperity angle is 45°, the shear stress gradually tends to residual strength after reaching the peak shear stress, and there is a one-to-one correspondence between normal displacement evolution and shear stress. With the increase of the asperity angles, the shear stiffness increases gradually. With the increase of normal stiffness, the peak shear stress of structural planes with 15° and 45° asperity angles increases linearly, and when the asperity angle is 30°, it presents the characteristic of piecewise function, but the peak shear dilatancy angle gradually decreases. The failure mode of the structural plane is obtained by analyzing the mass loss before and after shearing, the proportion of debris particle size, and the evolution of three-dimensional morphology parameters. When the fluctuation angles are 15° and 45°, the failure modes are relatively single, namely wear failure and tooth cutting failure. When the fluctuation angle is 30°, the failure mode has a strong and complex dependence on the experimental conditions, mainly including tooth tip shear failure and full tooth cutting failure. By combining the three-dimensional spatial point cloud data of the structural plane with the normal displacement values at the corresponding shear displacement, a simulated cloud map of the structural plane gap width at a specific shear displacement is obtained, which analyzes the dynamic evolution process of the structural plane during the shear process and obtains its failure mechanism
Experimental study of the influence of drainage conditions on sandstone mechanics and its deformation localization characteristics
In order to study the deformation localization failure characteristics of sandstone under the coupling action of seepage and stress, the triaxial compression tests of sandstone under different drainage conditions were carried out using the visualized triaxial servo control test system combined with three-dimensional digital image correlation (3D-DIC). The rock mechanics, seepage and deformation localization characteristics were analyzed, and the micro-morphology of fracture surface after sandstone failure was analyzed using electron microscope scanning. The results shown that the peak strength and elastic modulus of sandstone under drainage condition were higher than those under undrained condition, the peak strength, elastic modulus and Poisson’s ratio of sandstone increased with the increasing seepage water pressure, the time point of penetration crack and maximum permeability would be advanced. When the seepage water pressure was the same, the localized zone of deformation field cloud map of the sand surface was wider in the undrained condition than that in the drained condition, i.e., the macroscopic crack of rock was more obvious. Water flow under drained condition took away the mineral particles inside the rock and formed holes, the rupture surface of which was smoother than that under undrained condition, whereas flakes cuttings were obviously attached to the surface of the particles under undrained condition. The initiation point of radial deformation localization was consistently higher than that of axial deformation localization for all drainage conditions, with an average increase of 1.23%. The initiation stress levels of the radial and axial deformation localization increased with increasing seepage water pressure, i.e., the initiation time point was earlier. The radial and axial initiation stress level of sandstone under drainage condition were higher than those under undrained condition, with an average increase of 1.85% and 2.21% respectively. When the water pressure was the same, the initiation stress and stress level were more significantly affected by water pressure in the undrained condition than in the drained condition
Anticipation, learning and welfare : the case of distortionary taxation
Revise and resubmit in Journal of Economic Dynamics and ControlWe study the impact of anticipated fiscal policy changes in a Ramsey economy where agents form long-horizon expectations using adaptive learning. We ex- tend the existing framework by introducing distortionary taxes as well as elastic labour supply, which makes agents' decisions non-predetermined but more realistic. We detect that the dynamic responses to anticipated tax changes under learning have oscillatory behaviour that can be interpreted as self-ful lling waves of optimism and pessimism emerging from systematic forecast errors. Moreover, we demonstrate that these waves can have important implications for the welfare consequences of fiscal reforms.Publisher PD
Satellite Availability and Service Performance Evaluation for Next-Generation GNSS, RNSS and LEO Augmentation Constellation
Positioning accuracy is affected by the combined effect of user range errors and the geometric distribution of satellites. Dilution of precision (DOP) is defined as the geometric strength of visible satellites. DOP is calculated based on the satellite broadcast or precise ephemerides. However, because the modernization program of next-generation navigation satellite systems is still under construction, there is a lack of real ephemerides to assess the performance of next-generation constellations. Without requiring real ephemerides, we describe a method to estimate satellite visibility and DOP. The improvement of four next-generation Global Navigation Satellite Systems (four-GNSS-NG), compared to the navigation constellations that are currently in operation (four-GNSS), is statistically analyzed. The augmentation of the full constellation the Quasi-Zenith Satellite System (7-QZSS) and the Navigation with Indian Constellation (11-NavIC) for regional users and the low Earth orbit (LEO) constellation enhancing four-GNSS performance are also analyzed based on this method. The results indicate that the average number visible satellites of the four-GNSS-NG will reach 44.86, and the average geometry DOP (GDOP) will be 1.19, which is an improvement of 17.3% and 7.8%, respectively. With the augmentation of the 120-satellite mixed-orbit LEO constellation, the multi-GNSS visible satellites will increase by 5 to 8 at all latitudes, while the GDOP will be reduced by 6.2% on average. Adding 7-QZSS and 11-NavIC to the four-GNSS-NG, 37.51 to 71.58 satellites are available on global scales. The average position DOP (PDOP), horizontal DOP (HDOP), vertical DOP (VDOP), and time DOP (TDOP) are reduced to 0.82, 0.46, 0.67 and 0.44, respectively
Evaluating Supplier Management Maturity in Prefabricated Construction Project-Survey Analysis in China
Prefabrication is considered as a modern method of construction, transferring part of on-site work into factories and generating a new decoupling point in supply chain. Management of prefabricated component (PC) suppliers plays a key role in the performance of prefabricated construction project (PCP). Evaluating and improving supplier management maturity (SMM) become critical issues for large contractors. Previous research on PCP supply chain mainly focused on technology, process and performance aspects, while paying little attention to supplier relationship management. This study proposes an assessment criteria system of supplier management from five dimensions, including procurement process, operation efficiency, relationship coordination and strategy alignment and corporate social responsibility. A maturity grid with five levels is designed to present continuous improvement of supplier management. 34 large PCP construction firms listed in contractor directory were investigated in China through semi-structured interview and questionnaire survey. Independent two-samples t-test and one-way analysis of variance were adopted to explore SMM of different groups according to business scope, procurement method and construction experience. The results indicate that the overall maturity level of supplier management is relatively low, implying that supply activity cannot achieve inter-organization integration. Management on relationship coordination and strategy alignment lag behind procurement management and operation efficiency. Single business contractors have higher SMM than diversified ones. Contractors integrated in engineering, procurement and construction are superior to design-bid-build contractors in supplier management, especially in relationship coordination and strategic alignment. Construction experience is conductive to supplier operation efficiency. Noticeably, there are no statistically significant differences in the performance of corporate social responsibility among different groups. These results will contribute to developing a benchmark framework for contractors to evaluate SMM and achieve continuous improvements in PCP
Cycle Slip Detection and Repair for Dual-Frequency LEO Satellite GPS Carrier Phase Observations with Orbit Dynamic Model Information
Cycle slip detection and repair are crucial for precise GPS-derived orbit determination of the low-Earth orbit (LEO) satellites. We present a new approach to detect and repair cycle slips for dual-frequency LEO satellite GPS observations. According to Newton’s equation of motion, the second-order time difference of the LEO satellite’s position (STP) is only related to the sampling interval and the satellite’s acceleration, which can be precisely obtained from the known orbit dynamic models. Then, several kinds of second-order time-difference geometry-free (STG) phase combinations, taking full advantage of the correlation between the satellite orbit variations and the dynamic model, with different level of ionospheric residuals, are proposed and adopted together to detect and fix cycle slips. The STG approach is tested with some LEO satellite GPS datasets. Results show that it is an effective cycle slip detection and repair method for LEO satellite GPS observations. This method also has some important features. Firstly, the STG combination is almost independent of the pseudorange. Secondly, this method is effective for LEO satellites, even in real-time application. Thirdly, this method is suitable for ground-based GPS receivers if we know the acceleration of the receivers
- …