Pairwise interactive knowledge and Nash equilibrium

We provide epistemic conditions for Nash equilibrium, which are considerably weaker than thestandard ones by Aumann and Brandenburger (1995). Indeed, we simultaneously replace commonknowledge of conjectures and mutual knowledge of rationality with strictly weaker epistemicconditions of pairwise common knowledge of conjectures and pairwise mutual knowledge ofrationality respectively. It is also shown that, unlike the Aumann and Brandenburger''s conditions,ours do not imply common knowledge of rationality. Surprisingly, they actually do not even implymutual knowledge of rationality.microeconomics ;

Growth, globalization, and gains from the Uruguay Round

Emphasizing the importance of evaluating the Uruguay Round in the context of a changing world economy, the authors base their projections on a model that incorporates certain economic shifts: 1) that the center of economic gravity will shift toward the South and toward Asia (a shift that is already under way and shows no signs of abating), and 2) that the pattern of comparative advantage will continue to change, with the East Asian economies gaining comparative advantage in the production of physical and human-capital-intensive products. The authors argue that these changes in the global economy significantly affect their analysis of the Uruguay round reforms, for two reasons. First, with the global distribution of trade and production shifting toward Asia, the deeper Uruguay Round cuts inthat region become more important, giving rise to a 17 percent increase in the proportionate welfare gain after implementation of tariff cuts. Second, without the Round, almost all of the bilateral quotas associated with the Multifibre Arrangement (MFA) would have become more binding and the resulting distortion would have been significantly greater. In this analysis, the global gain from MFA reform is 60 percent greater than it would have been without taking into account the effects of growth. Of course, procedures for implementation of the MFA reforms are more complex than they have conveyed for purposes of analysis. In practice, one must also consider the impact of accel quota growth under the Agreement on Textiles and Clothing. But even when the Agreement on Textiles and Clothing is implemented over the period for which projections were made, quota rents rise for many bilateral flows. This is a consequence both of shifts in comparative advantage toward the supplying countries and of simultaneous cuts in tariffs on textiles and clothing. The projections approach used here may be viewed as a logical extension of the growing econometric literature seeking to explain the determinants of economic growth through regression analysis. By offering a bridge between econometric evidence and computable general equilibrium modeling, the authors hope to combine the two approaches to help shed light on the interaction between trade reform and economic growth.Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Export Competitiveness,Globalization and Financial Integration,Environmental Economics&Policies,Trade and Regional Integration,Achieving Shared Growth,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT

Structure‐preserving transformations of epistemic models

The prevailing approaches to modelling interactive uncertainty with epistemic models in economics are state-based and type-based. We explicitly formulate two general procedures that transform state models into type models and vice versa. Both transformation procedures preserve the belief hierarchies as well as the common prior assumption. By means of counterexamples it is shown that the two procedures are not inverse to each other. However, if attention is restricted to maximally reduced epistemic models, then isomorphisms can be constructed and an inverse relationship emerges

Two definitions of correlated equilibrium

Correlated equilibrium constitutes one of the basic solution concepts for static games with complete information. Actually two variants of correlated equilibrium are in circulation and have been used interchangeably in the literature. Besides the original notion due to Aumann (1974), there exists a simplified definition typically called canonical correlated equilibrium or correlated equilibrium distribution. It is known that the original and the canonical version of correlated equilibrium are equivalent from an ex-ante perspective. However, we show that they are actually distinct - both doxastically as well as behaviourally - from an interim perspective. An elucidation of this difference emerges in the reasoning realm: while Aumann's correlated equilibrium can be epistemically characterized by common belief in rationality and a common prior, canonical correlated equilibrium additionally requires the condition of one-theory-per-choice. Consequently, the application of correlated equilibrium requires a careful choice of the appropriate variant. (c) 2020 Elsevier B.V. All rights reserved

Effects of Vapor Injected Compression, Hybrid Evaporator Flow Control, and Other Parameters on Seasonal Energy Efficiency.

A companion paper (Bach et al. 2014) experimentally investigated the effects of vapor injected compression and hybrid evaporator flow control on capacity and COP. The goal of this paper is to provide insight into the effects of these technologies on heating seasonal performance (HSPF). HSPF was calculated using a modified version of the ANSI/AHRI 210/240 method, and parametric studies were performed to better understand the seasonal performance with a focus on comparing vapor injected and single stage system configuration. It was found that part load degradation and reduced capacity at low ambient temperature are factors that can degrade the seasonal performance. The increase in heat pump COP for the vapor injected configuration leads to only a small benefit - the main contributor to the increased HSPF of the vapor injected system configuration is its increased capacity towards low ambient temperatures. References: Bach C. K., Vetsch, B., Groll, E. A., Braun, J. E., and Horton, W. T, (2014), Experimental Investigation of Vapor Injected Compression for Cold Climate Heat Pumps and its Effects on their Performance, 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette

Interleaved Circuitry And Hybrid Control As Means To Reduce The Effects Of Flow Maldistribution.

Flow maldistribution in evaporators can lead to significant degradation of capacity and efficiency of vapor compression equipment. A significant amount of work has previously been done to mend these issues. For variable air flow maldistribution, refrigerant compensation was proposed to reduce the performance degradation. For fixed air side maldistribution, refrigerant circuitry modifications were proposed to significantly reduce the effects of the maldistribution. However, no work has been found on modifying the refrigerant circuitry to make it less vulnerable to varying air side maldistribution. The purpose of this paper is to fill this gap in open literature. The performance of the new, interleaved circuitry approach and an active refrigerant flow control is compared to the standard circuitry for different cases of maldistribution. The results show that the interleaved circuitry recovers less of the performance losses than equalization of the exit superheats. However, the implementation cost in an actual system is expected to be significantly lower and the long term reliability is expected to be much better than for an active control approach

Experimental Investigation of Vapor Injected Compression for Cold Climate Heat Pumps

Building heating requirements increase with decreasing ambient temperature, while the coefficient of performance of air-source heat pumps (ASHPs) shows the opposite trend. Additionally, heating capacity decreases with ambient temperature, which leads to the utilization of inefficient electric reheat below the design point. Increasing the capacity and COP at lower ambient temperatures is important for improving the market penetration of heat pumps in climates having significant operating time at low ambient temperature. Simulation studies previously showed that compressor vapor injection leads to an increase of COP under exactly those conditions. Furthermore, reduced capacity degradation towards smaller ambient temperatures was predicted. The work presented in this paper shows experimental results obtained from a commercially available 5-ton heat pump that was retrofitted with a two-port vapor injected scroll compressor. The injection ports within the two compression pathways are located in the fixed scroll with different distance from the suction chamber. The vapor for the two injection pressure levels was generated using two vapor separators in a cascade configuration. This configuration made it necessary to not only control the superheat but also the liquid levels in the separators and subcooling of the refrigerant leaving the condenser. Baseline performance data of the heat pump without vapor injection was obtained and compared with that for the vapor injection and other system configurations. For the baseline, the injection lines to the compression pockets were plugged within the fixed scroll to reduce dead volume and re-expansion losses. Also, the vapor-separator section was shut off and bypassed. In the second step, the plugs were removed and a staged expansion process was performed using the separator section. The generated vapor from each separator was injected into the respective compressor port causing an intercooling effect on the compression process. With identical compressor speed, a 28% improvement in capacity was achieved at the 8.33°C (47 F) design point, when compared to the baseline without vapor injection. When the baseline and vapor injected system capacity were matched by adjusting compressor speed, the COP increased by up to 6% at -8.33°C (17 F). Preliminary results of a bin-type analysis of the experimental data predicts an improvement in HSPF of 6% for Minneapolis and nearly 7% for AHRI climate region 5. The benefit is mainly caused by a reduction of the auxiliary electric heater’s runtime

Application Of Oil Flooded Compression With Regeneration To A Packaged Heat Pump System

Heating capacity and coefficient of performance (COP) of conventional air-source heat pumps decreases towards lower ambient temperatures. In addition, high discharge temperature cutout at the compressor outlet might limit the operation of the heat pump at very low ambient temperatures. Oil injected into the compression chamber absorbs part of the heat generated during the compression process, which can result in significant reduction of the compressor discharge temperature. Discharge temperature therefore decreases with increasing injected oil mass fraction, especially at low ambient temperatures. Therefore, oil injection allows the application of air-source heat pumps in regions with very low ambient temperature in winter. Additionally, oil injection decreases the compressor power consumption by providing better sealing and lower friction during the compression process. Furthermore, if oil injection is combined with a regenerative heat exchanger, the system performance of a vapor compression system can be improved significantly. The work presented on this paper shows the experimental results of a 5-ton (17.6 kW) R410A packaged heat pump which was retrofitted with an oil injected compressor and regenerator. The effect of different oil mass fractions on the system performance was investigated under standard AHRI 210/240 heating test conditions. According to the results, more than 7% system COP improvement was observed compared to the baseline system

Construction of the Pauli-Villars-regulated Dirac vacuum in electromagnetic fields

Using the Pauli-Villars regularization and arguments from convex analysis, we construct solutions to the classical time-independent Maxwell equations in Dirac's vacuum, in the presence of small external electromagnetic sources. The vacuum is not an empty space, but rather a quantum fluctuating medium which behaves as a nonlinear polarizable material. Its behavior is described by a Dirac equation involving infinitely many particles. The quantum corrections to the usual Maxwell equations are nonlinear and nonlocal. Even if photons are described by a purely classical electromagnetic field, the resulting vacuum polarization coincides to first order with that of full Quantum Electrodynamics.Comment: Final version to appear in Arch. Rat. Mech. Analysi

TotalSegmentator: robust segmentation of 104 anatomical structures in CT images

We present a deep learning segmentation model that can automatically and robustly segment all major anatomical structures in body CT images. In this retrospective study, 1204 CT examinations (from the years 2012, 2016, and 2020) were used to segment 104 anatomical structures (27 organs, 59 bones, 10 muscles, 8 vessels) relevant for use cases such as organ volumetry, disease characterization, and surgical or radiotherapy planning. The CT images were randomly sampled from routine clinical studies and thus represent a real-world dataset (different ages, pathologies, scanners, body parts, sequences, and sites). The authors trained an nnU-Net segmentation algorithm on this dataset and calculated Dice similarity coefficients (Dice) to evaluate the model's performance. The trained algorithm was applied to a second dataset of 4004 whole-body CT examinations to investigate age dependent volume and attenuation changes. The proposed model showed a high Dice score (0.943) on the test set, which included a wide range of clinical data with major pathologies. The model significantly outperformed another publicly available segmentation model on a separate dataset (Dice score, 0.932 versus 0.871, respectively). The aging study demonstrated significant correlations between age and volume and mean attenuation for a variety of organ groups (e.g., age and aortic volume; age and mean attenuation of the autochthonous dorsal musculature). The developed model enables robust and accurate segmentation of 104 anatomical structures. The annotated dataset (https://doi.org/10.5281/zenodo.6802613) and toolkit (https://www.github.com/wasserth/TotalSegmentator) are publicly available.Comment: Accepted at Radiology: Artificial Intelligenc