Future Ground Research Articles

Prediction of the ground temperature variations caused by the operation of GSHP system with ANN

Ground temperature is an important factor that affects the operation efficiency of ground source heat pump (GSHP) systems. Therefore, it is very important to acquire the ground temperature variations, which can be realized by means of sensor measurements or software simulations. But the monitor system sometimes may be ineffective or inaccurate because of the faulty operation of sensors. And also, the conventional physical models have some limitations in obtaining the detailed ground temperature variations caused by the long term operation of GSHP systems. However, an advantage of the measurement system is that a large amount of monitored data of the ground temperature could be obtained, which provide good solutions for the prediction by black-box methods. In this study, artificial neural network (ANN) was adopted for the prediction of the disturbed ground temperature caused by a vertical GSHP system. Two predictions were conducted with this method. The first is that future variations of the average ground temperature within 100 m deep during the long term operation of GSHP system were predicted with enough accuracy using ANN by 'UseParallel' and 'UseGPU' methods. It has been found that, for the average ground temperature prediction, 'UseParallel' is superior to 'UseGPU' in prediction accuracy, but inferior in calculation speed. The second is that the missing data of the monitored ground temperature variations were supplemented with the ANN model. Mean relative error (MRE), max relative error (MAE), mean square error (MSE) and absolute fraction of variance (R2) of the ANN model are 0.3223%, 9.8999%, 0.5036% and more than 0.9994, respectively. The second ANN model could predict the missing data, but failed in predicting the future detailed ground temperature, which should be further improved in the future.

A deep sequence‐to‐sequence method for accurate long landing prediction based on flight data

In civil aviation industry, runway overrun is a typical landing safety incident concerned by both airlines and authorities. Among various contributing factors to the runway overrun incident, long landing plays an important role. However, existing studies for long landing prediction mainly depend on classic machine learning methods and handcrafted features. As a result, they usually require much expert knowledge and provide unsatisfactory results. To address these problems, this paper proposes an innovative deep sequence-to-sequence model which utilizes QAR (Quick Access Recorder) data for accurate long landing pre- diction. Specifically, to cope with the high heterogeneity of QAR dataset, a data pre-processing procedure is first proposed which includes data cleaning, interpolation and normalization steps. Second, to avoid the noises incurred by too many QAR parameters and relieve the reliance on expert experience, the GBDT (gradient boosting decision trees) model is employed to choose the most relevant parameters as features. Then a CNN-LSTM and TG-attention encoder-decoder architecture is proposed to accurately predict future aircraft ground speed and radio height sequences, based on which the touchdown distance can be finally calculated. Experimental results on a large QAR dataset with 44,176 A321 flights validate effectiveness of the proposed method.

From grief to hope in conservation.

From grief to hope in conservation.

From scenario-based seismic hazard to scenario-based landslide hazard: fast-forwarding to the future via statistical simulations

Ground motion scenarios exists for most of the seismically active areas around the globe. They essentially correspond to shaking level maps at given earthquake return times which are used as reference for the likely areas under threat from future ground displacements. Being landslides in seismically actively regions closely controlled by the ground motion, one would expect that landslide susceptibility maps should change as the ground motion patterns change in space and time. However, so far, statistically-based landslide susceptibility assessments have primarily been used as time-invariant.In other words, the vast majority of the statistical models does not include the temporal effect of the main trigger in future landslide scenarios. In this work, we present an approach aimed at filling this gap, bridging current practices in the seismological community to those in the geomorphological and statistical ones. More specifically, we select an earthquake-induced landslide inventory corresponding to the 1994 Northridge earthquake and build a Bayesian Generalized Additive Model of the binomial family, featuring common morphometric and thematic covariates as well as the Peak Ground Acceleration generated by the Northridge earthquake. Once each model component has been estimated, we have run 1000 simulations for each of the 217 possible ground motion scenarios for the study area. From each batch of 1000 simulations, we have estimated the mean and 95% Credible Interval to represent the mean susceptibility pattern under a specific earthquake scenario, together with its uncertainty level. Because each earthquake scenario has a specific return time, our simulations allow to incorporate the temporal dimension into any susceptibility model, therefore driving the results toward the definition of landslide hazard. Ultimately, we also share our results in vector format – a .mif file that can be easily converted into a common shapefile –. There, we report the mean (and uncertainty) susceptibility of each 1000 simulation batch for each of the 217 scenarios.

Improving Engine-Room Ground Resistance of a Power Source by Changing the Reference Point and Ground Reinforcement

In the engine room ground reinforcement work that secures the stability of the electrical device added in the first vehicle and reduces the ground resistance due to the aging of the vehicle, the existing battery ground standard work method and the main power source of the vehicle while driving By experimenting the method of changing the reference point to the alternator ground, we are trying to present a reasonable ground path. For engine blocks used as ground paths and cables used as reinforcing materials in an engine room environment where high heat is generated, TCR values according to temperature changes are measured and used as data for selection of reinforced cables. In addition, as a way to check the effect of ground reinforcement, experiment with changes in engine load factor, shift time lag of automatic transmission, and change in headlight operating current to confirm the objectivity of the ground reinforcement effect, and based on the results obtained from the experiment. It will be used as data that can be referenced in future engine room ground reinforcement work.

Exclamations and their discourse effects in Japanese

This paper discusses two kinds of sentences with nante that can express exclamations in Japanese. I show that these two nante exclamations show the contrast observed between sentence exclamations and wh-exclamatives in English (Rett 2011). Based on the data, I propose that nante in the two types of sentences can be analyzed in a unified way: nante is like what in English in that it can range over a variety of categories. The semantic composition shows that the two nante sentences have different sentence types and hence different discourse effects (Farkas & Roelofsen 2017). One type is a marked assertion, and the other is a bonafide exclamative. I show the contrast using the discourse model in Farkas & Bruce (2010): the exclamative updates the speaker’s commitment, not the potential future common ground.

Stellar map centroid positioning based on dark channel denoising and feasibility of jitter detection on ZiYuan3 satellite platform

Stellar map denoising and centroid positioning, which directly determine the postpositioning accuracy of star trackers, are key technologies in stellar map processing. Due to the influence of a complex starry sky background, there is often a large amount of noise in stellar maps, which makes it difficult to accurately locate the stellar centroid. A stellar map processing method based on dark channel denoising and continuous multiframe stellar map centroid positioning combined with centroid trajectory constraints is proposed. First, a dark channel noise template is used for denoising, and the single-point and multipoint noises in the denoising result are filtered. Second, in the process of stellar map positioning, if the maximum gray value of the stellar is not unique, it is constrained by the previous stellar positioning result, an adaptive window is established, and the gray-scale centroid weighting method is used to locate the centroid. Then, the star angular distance is used to analyze the precision of the centroid positioning. Finally, the jitter frequency of the satellite platform based on the continuous multiframe centroid positioning result is used to detect satellite attitude. The experimental results show that the performance of dark channel denoising, which can solve many strip noise and background noise problems in stellar maps, is better than that of the existing stellar map denoising method. The centroid positioning results improves the star angular distance by 18.85 arc sec compared with the Gaussian filter and by 8.03 arc sec compared with the global threshold segmentation method, significantly improving the accuracy of stellar map centroid positioning and laying a foundation for improving the star tracker positioning accuracy. A jitter frequency of 0.67 Hz was detected on the ZiYuan3 satellite platform based on the centroid positioning results. It enriches the jitter detection methods and provides a theoretical and technical basis for the design of future high-resolution ground observation remote sensing satellite platforms and geometric accuracy compensation.

CFD Simulations of Allothermal Steam Gasification Process for Hydrogen Production

The article presents an experimental laboratory setup used for the empirical determination of the gasification of coal samples in the form of solid rock, cut out in the form of a cylinder. An experimental laboratory set enabled a series of experiments carried out at 700 °C with steam as the gasification agent. The samples were prepared from the coal seam, the use of which can be planned in future underground and ground gasification experiments. The result of the conducted coal gasification process, using steam as the gasification agent, was the syngas, including hydrogen (H2) with a concentration between 46% and 58%, carbon dioxide (CO2) with a concentration between 13% and 17%, carbon monoxide (CO) with a concentration between 7% and 11.5%, and methane(CH4) with a concentration between 9.6% and 20.1%.The results from the ex-situ experiments were compared with the results of numerical simulations using computational fluid dynamics (CFD) methods. A three-dimensional numerical model for the coal gasification process was developed using Ansys-Fluent software to simulate an ex-situ allothermal coal gasification experiment using low-moisture content hard coal under atmospheric conditions. In the numerical model, the mass exchange (flow of the gasification agent), the turbulence description model, heat exchange, the method of simulating the chemical reactions, and the method of mapping the porosity medium were included. Using the construction data of an experimental laboratory set, a numerical model was developed and its discretization (development of a numerical grid, based on which calculations are made) was carried out. Tip on the reactor, supply method, and parameters maintained during the gasification process were used to define the numerical model in the Ansys-Fluent code. A part of the data were supplemented on the basis of literature sources. Where necessary, the literature parameters were converted to the conditions corresponding to the experiment, which were carried out. After performing the calculations, the obtained results were compared with the available experimental data. The experimental and the simulated results were in good agreement, showing a similar tendency.

Evolved massive stars at low-metallicity

We present a case study in which we used a novel method to identify red supergiant (RSG) candidates in NGC 6822 based on their 1.6 μm H-bump. We collected 32 bands of photometric data for NGC 6822 ranging from the optical to the mid-infrared, derived from Gaia, PS1, LGGS, VHS, UKIRT, IRSF, HAWK-I, Spitzer, and WISE. Using the theoretical spectra from MARCS, we demonstrate that there is a prominent difference around 1.6 μm (H-bump) between targets with high and low surface gravity (HSG and LSG). Taking advantage of this feature, we identify efficient color–color diagrams of rzH (r − z vs. z − H) and rzK (r − z vs. z − K) to separate HSG (mostly foreground dwarfs) and LSG targets (mainly background red giant stars, asymptotic giant branch stars, and RSGs) from crossmatching of optical and near-infrared (NIR) data. Moreover, synthetic photometry from ATLAS9 gives similar results. We further separated RSG candidates from the remaining LSG candidates as determined by the H-bump method by using semi-empirical criteria on NIR color–magnitude diagrams, where both the theoretic cuts and morphology of the RSG population are considered. This separation produced 323 RSG candidates. The simulation of foreground stars with Besançon models also indicates that our selection criteria are largely free from the contamination of Galactic giants. In addition to the H-bump method, we used the traditional BVR method (B − V vs. V − R) as a comparison and/or supplement by applying a slightly aggressive cut to select as many RSG candidates as possible (358 targets). Furthermore, the Gaia astrometric solution was used to constrain the sample, where 181 and 193 targets were selected with the H-bump and BVR method, respectively. The percentages of selected targets in the two methods are similar at ∼60%, indicating a comparable accuracy of the two methods. In total, there are 234 RSG candidates after combining targets from the two methods, and 140 (∼60%) of them are in common. The final RSG candidates are in the expected locations on the mid-infrared color–magnitude diagram with [3.6]−[4.5] ≲ 0 and J − [8.0] ≈ 1.0. The spatial distribution is also coincident with the far-ultraviolet-selected star formation regions, suggesting that the selection is reasonable and reliable. We indicate that our method can also be used to identify other LSG targets, such as red giants and asymptotic giant branch stars, and it can also be applied to most of the nearby galaxies by using recent large-scale ground-based surveys. Future ground- and space-based facilities may promote its application beyond the Local Group.

Systematic literature review on the security challenges of blockchain in IoT-based smart cities

PurposeSecurity is the most important issue in Internet of Things (IoT)-based smart cities and blockchain (BC). So, the present paper aims to detect and organize the literature regarding security in the IoT-based smart cities and BC context. It also proposes an agenda for future research. Therefore, the authors did a statistical review of security in IoT and BC in smart cities. The present investigation aims to determine the principal challenges and disturbances in IoT because of the BC adoption, the central BC applications in IoT-based smart cities and the BC future in IoT-based smart cities.Design/methodology/approachIoT) has a notable influence on modernizing and transforming the society and industry for knowledge digitizing. Therefore, it may be perceived and operated in real time. The IoT is undergoing exponential development in industry and investigation. Still, it contains some security and privacy susceptibilities. Naturally, the research community pays attention to the security and privacy of the IoT. Also, the academic community has put a significant focus on BC as a new security project. In the present paper, the significant mechanisms and investigations in BC ground have been checked out systematically because of the significance of security in the IoT and BC in smart cities. Electronic databases were used to search for keywords. Totally, based on different filters, 131 papers have been gained, and 17 related articles have been obtained and analyzed. The security mechanisms of BC in IoT-based smart cities have been ranked into three main categories as follows, smart health care, smart home and smart agriculture.FindingsThe findings showed that BC’s distinctive technical aspects might impressively find a solution for privacy and security problems encountering the IoT-based smart cities development. They also supply distributed storage, transparency, trust and other IoT support to form a valid, impressive and secure distributed IoT network and provide a beneficial guarantee for IoT-based smart city users’ security and privacy.Research limitations/implicationsThe present investigation aims to be comprehensive, but some restrictions were also observed. Owing to the use of some filters for selecting the original papers, some complete works may be excluded. Besides, inspecting the total investigations on the security topic in BC and the IoT-based smart cities is infeasible. Albeit, the authors attempt to introduce a complete inspection of the security challenges in BC and the IoT-based smart cities. BC includes significant progress and innovation in the IoT-based smart cities’ security domain as new technology. Still, it contains some deficiencies as well. Investigators actively encounter the challenges and bring up persistent innovation and inspection of related technologies in the vision of the issues available in diverse application scenarios.Practical implicationsThe use of BC technology in finding a solution for the security issues of the IoT-based smart cities is a research hotspot. There is numerable literature with data and theoretical support despite the suggestion of numerous relevant opinions. Therefore, this paper offers insights into how findings may guide practitioners and researchers in developing appropriate security systems dependent upon the features of IoT-based smart city systems and BC. This paper may also stimulate further investigation on the challenge of security in BC and IoT-based smart cities. The outcomes will be of great value for scholars and may supply sights into future investigation grounds in the present field.Originality/valueAs the authors state according to their knowledge, it is the first work using security challenges on BC and IoT-based smart cities. The literature review shows that few papers discuss how solving security issues in the IoT-based smart cities can benefit from the BC. The investigation suggests a literature review on the topic, recommending some thoughts on using security tools in the IoT-based smart cities. The present investigation helps organizations plan to integrate IoT and BC to detect the areas to focus. It also assists in better resource planning for the successful execution of smart technologies in their supply chains.

Hierarchical Inference with Bayesian Neural Networks: An Application to Strong Gravitational Lensing

Abstract In the past few years, approximate Bayesian Neural Networks (BNNs) have demonstrated the ability to produce statistically consistent posteriors on a wide range of inference problems at unprecedented speed and scale. However, any disconnect between training sets and the distribution of real-world objects can introduce bias when BNNs are applied to data. This is a common challenge in astrophysics and cosmology, where the unknown distribution of objects in our universe is often the science goal. In this work, we incorporate BNNs with flexible posterior parameterizations into a hierarchical inference framework that allows for the reconstruction of population hyperparameters and removes the bias introduced by the training distribution. We focus on the challenge of producing posterior PDFs for strong gravitational lens mass model parameters given Hubble Space Telescope–quality single-filter, lens-subtracted, synthetic imaging data. We show that the posterior PDFs are sufficiently accurate (statistically consistent with the truth) across a wide variety of power-law elliptical lens mass distributions. We then apply our approach to test data sets whose lens parameters are drawn from distributions that are drastically different from the training set. We show that our hierarchical inference framework mitigates the bias introduced by an unrepresentative training set’s interim prior. Simultaneously, we can precisely reconstruct the population hyperparameters governing our test distributions. Our full pipeline, from training to hierarchical inference on thousands of lenses, can be run in a day. The framework presented here will allow us to efficiently exploit the full constraining power of future ground- and space-based surveys (https://github.com/swagnercarena/ovejero).

Basin effects and limitations of 1D site response analysis from 2D numerical models of the Thorndon basin

Plane strain (2D) finite element models are used to examine factors contributing to basin effects observed for multiple seismic events at sites in the Thorndon basin of Wellington, New Zealand. The models consider linear elastic soil and rock response when subjected to vertically-propagating shear waves. Depth-dependent shear wave velocities are considered in the soil layers, and the effects of random variations of soil velocity within layers are modelled. Various rock shear wave velocity configurations are considered to evaluate their effect on the modelled surficial response. It is shown that these simple 2D models are able to capture basin reverberations and compare more favourably to observations from strong motion recordings than conventional 1D site response models. It is also shown that consideration of a horizontal impedance contrast across the Wellington Fault affects spectral response and amplification at longer periods, suggesting the importance of this feature in future ground motion modelling studies in the Wellington region.

Adaptive Optics pre-compensated laser uplink to LEO and GEO.

We present the results from a Monte Carlo computer simulation of adaptive optics (AO) pre-compensated laser uplink propagation through the Earth's atmospheric turbulence from the ground to orbiting satellites. The simulation includes the so-called point-ahead angle and tests several potential AO mitigation modes such as tip/tilt or full AO from the downlink beam, and a laser guide star at the point ahead angle. The performance of these modes, as measured by metrics relevant for free-space optical communication, are compared with no correction and perfect correction. The aim of the study is to investigate fundamental limitations of free-space optical communications with AO pre-compensation and a point-ahead angle, therefore the results represent an upper bound of AO corrected performance, demonstrating the potential of pre-compensation technology. Performance is assessed with varying launch aperture size, wavelength, launch geometry, ground layer turbulence strength (i.e. day/night), elevation angle and satellite orbit (Low-Earth and Geostationary). By exploring this large parameter space we are able examine trends on performance with the aim of informing the design of future optical ground stations and demonstrating and quantifying the potential upper bounds of adaptive optics performance in free-space optical communications.

Rotational Drive-Versus-Quality and Video Compression-Versus-Delay Analysis for Multi-Channel Video Streaming System on Ground Combat Vehicles

The multi-channel video streaming system is an essential device for future ground combat vehicles. For the system, the application of digital interfaces is required instead of the direct analog method to support selectable multiple channels. However, due to the characteristics of the digital interfaces that require en/decoding and signal conversion, the system should support the ability to adapt to quality and delay requirements depending on how video data is utilized. To support addressed issue, this study designs and emulates the multi-channel compressed-video streaming system of ground combat vehicle's fire control system based on commercial standards. Using the system, this study analyzes the quality of video according to the rotational speed of the acquisition device and Glass-to-Glass (G2G) delay between video acquisition and display devices according to video compression rates. Through these experiments and analysis, this paper presents the design direction of the system having scalability on the latest technology while providing high-quality video data streaming flexibly. Keywords: 지상 ì „íˆ¬ 차량, 사격 í†µì œ ì‹œìŠ¤í œ, 다채널 스트리밍, 비디오 품질, 화면 간 지연 Keywords: Ground Combat Vehicle, Fire Control System, Multi-Channel Streaming, Video Quality, Glass-to-Glass Delay

Logging the Lambeth Group Upper Shelly Beds for the Thames Tideway Tunnel in London, UK: More than just “dark grey clay with shells”

Despite recent advances in the procedures for logging rotary borehole core, the Lambeth Group Upper Shelly Beds are often inadequately characterised during ground investigations for underground construction. With no recognised industry guidance, there has been a lack of clarity and detail in many logging records, other than a generic description of “dark grey clay with many shells and (local) hard bands.” Improvements in describing these deposits have been hindered by the relatively limited extent of their subcrop and rarity of surface exposure, allied to a lack of precedent intersection during underground construction excavation.Geological logging during construction of the Thames Tideway Tunnel has revealed a laterally continuous sequence of strata within the Upper Shelly Beds through central London. This ranges in lithology from strongly indurated shell ‘coquinas’, mudstones and limestones to organic-rich laminated clays, silts and fine sands. Abrupt changes in lithology and fossil fauna are displayed across sharp contacts between beds, indicative of rapid fluctuations in sea level (and so potentially of climate change) during the period of deposition.Notwithstanding their comparatively limited thickness of between 1.4 and 1.6 m within the area of investigation, the Upper Shelly Beds represent significant challenges for underground construction, most notably a reduction in the rate of excavation through the stronger layers of material. Early identification of the sequence has enabled modification and improvement to the on-site construction cycle and provided valuable assurance for the existing engineering design.This paper is intended to provide guidance for recognising the sequence of strata within the Upper Shelly Beds during future ground investigations in central London, with similar benefits for early recognition of the stronger layers during engineering design.

On-Line Learning and Updating Unmanned Tracked Vehicle Dynamics

Increasing levels of autonomy impose more pronounced performance requirements for unmanned ground vehicles (UGV). Presence of model uncertainties significantly reduces a ground vehicle performance when the vehicle is traversing an unknown terrain or the vehicle inertial parameters vary due to a mission schedule or external disturbances. A comprehensive mathematical model of a skid steering tracked vehicle is presented in this paper and used to design a control law. Analysis of the controller under model uncertainties in inertial parameters and in the vehicle-terrain interaction revealed undesirable behavior, such as controller divergence and offset from the desired trajectory. A compound identification scheme utilizing an exponential forgetting recursive least square, generalized Newton–Raphson (NR), and Unscented Kalman Filter methods is proposed to estimate the model parameters, such as the vehicle mass and inertia, as well as parameters of the vehicle-terrain interaction, such as slip, resistance coefficients, cohesion, and shear deformation modulus on-line. The proposed identification scheme facilitates adaptive capability for the control system, improves tracking performance and contributes to an adaptive path and trajectory planning framework, which is essential for future autonomous ground vehicle missions.

The GLINT South testbed for nulling interferometry with photonics: Design and on-sky results at the Anglo-Australian Telescope

AbstractIn 1978, Bracewell suggested the technique of nulling interferometry to directly image exoplanets which would enable characterisation of their surfaces, atmospheres, weather, and possibly determine their capacity to host life. The contrast needed to discriminate starlight reflected by a terrestrial-type planet from the glare of its host star lies at or beyond a forbidding$10^{-10}$for an exo-Earth in the habitable zone around a Sun-like star at near-infrared wavelengths, necessitating instrumentation with extremely precise control of the light. Guided Light Interferometric Nulling Technology (GLINT) is a testbed for new photonic devices conceived to overcome the challenges posed by nulling interferometry. At its heart, GLINT employs a single-mode nulling photonic chip fabricated by direct-write technology to coherently combine starlight from an arbitrarily large telescope at 1 550 nm. It operates in combination with an actuated segmented mirror in a closed-loop control system, to produce and sustain a deep null throughout observations. The GLINT South prototype interfacesthe 3.9-m Anglo-Australian Telescope and was tested on a sample of bright Mira variable stars. Successful and continuous starlight injection into the photonic chip was achieved. A statistical model of the data was constructed, enabling a data reduction algorithm to retrieve contrast ratios of about$10^{-3}$. As a byproduct of this analysis, stellar angular diameters that were below the telescope diffraction limit($\sim$100 mas) were recovered with1$\sigma$accuracy and shown to be in agreement with literature values despite working in the seeing-limited regime. GLINT South serves as a demonstration of the capability of direct-write photonic technology for achieving coherent, stable nulling of starlight, which will encourage further technological developments towards the goal of directly imaging exoplanets with future large ground based and space telescopes.

A Review of Multibeam Phased Array Antennas as LEO Satellite Constellation Ground Station

Small satellites in low Earth orbit (LEO) are typically organized as a satellite constellation. The satellite number of a LEO satellite constellation would be several hundred or even tens of thousands to realize a fully global coverage. This imposes a big challenge on ground station for satellite ordinary management and control operation. Phased array antennas are considered as attractive candidates for future satellite ground station. The primary reason is that phased array antennas can produce numbers of beams by the beamforming network thus support multiple satellites simultaneously. This paper aims to provide a tutorial-like review on phased array antennas as satellite ground station. The advantages of phased array antennas for this application are summarized by comparing them with traditional reflector antennas. Several array geometries for realizing the hemispherical coverage required for satellite tracking are presented. System architecture are given, and some considerations for engineering practice about phased array antenna based satellite ground station are also discussed.

New Puzzles in International Tax Agreements

The G-7’s “global minimum tax” accord—followed by a new version of the OECD’s “Two Pillar Solution” and its endorsement by the G-20—is accepted by many as evidence for international tax cooperation. But recent policy discussions offer no answer to a basic question: What can countries cooperate to achieve? This Article shows that the answers provided by proponents of the new international tax agreement are alarmingly ad hoc, misleading, and incoherent. Scholarship on corporate taxation has also long failed to identify potentials for international cooperation. The more successful international agreements purport to be, in other words, the more puzzling they become. I first examine three rationales recently identified for collective action. The first alleges a transformation in the services trade that supposedly undermines premises of traditional international tax design. The second emphasizes the international community’s need to appease the United States and prevent the latter from starting trade wars. Both make unusual and untenable factual and normative assumptions. A third rationale seems more familiar—countries should cooperate to end tax competition and multinational companies’ tax avoidance—but is at odds with both economic theory and the actual content of the OECD’s proposal. Theoretically, ending tax competitions—whether for productive capital or for corporate headquarters—cannot create gains for all countries. And in terms of policy content, the OECD proposal can more plausibly be read as limiting, rather than enhancing, governments’ capacities to tax MNCs. Older and more basic puzzles in theories of international taxation—concerning source-country taxation, residence countries’ unilateral relief from double taxation, and bilateral tax treaties—compound these new puzzles. Arguably, these puzzles have led tax scholars to abandon a basic social scientific template for explaining cooperation. Indeed, much of economic scholarship takes international tax institutions as exogenously given. I contrast this state of affairs with economic theories of trade agreements—in particular, with the way the “terms-of-trade” theory rationalizes the GATT/WTO regime. To emulate the success of the “terms-of-trade” theory, I argue, certain assumptions that have long prevailed in discourses about international taxation may need to be jettisoned. Only a more fundamental reconceptualization of the subject matter of international taxation can shed light on the true past and future grounds for international tax cooperation.

Channels for Common Ground

AbstractOne potentially ethically relevant feature of an utterance is that utterance's influence on the likelihoods that our future discourses wind up with one Stalnakerian ‘common ground’ or body of shared information rather than another. Such likelihoods matter ethically, so the ways our utterances influence them can matter ethically, despite the fact that such influences are often unintended, and often hard to see. By offering a relatively neutral descriptive framework that can enhance our collective sensitivity to and discussion of ethically, socially, and politically important features of language use, this paper contributes to the ethics of language use. It discusses ways in which utterances can influence the likelihoods of future common grounds by deploying one system of categorization rather than another, and argues that language’s effects on the evolution of discourse can affect the paths to and probabilities of different sorts of consensus.