Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission’s
Perseverance
rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband ...red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 μrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 μrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory
Curiosity
rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover’s Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover’s traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover’s sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.
The author describes a fast algorithm for local adaptive mesh refinement in n dimensions based on simplex bisection. A ready-to-use implementation of the algorithm in C++ pseudocode is given. It is ...proven that the scheme satisfies all conditions one usually places on grid refinement in the context of finite-element calculations. Bisection refinement also offers an interesting additional feature over the usual, regular, refinement scheme: all linear finite-element basis functions of one generation are of disjoint support. In the way the scheme is presented here, all generated simplex meshes satisfy a 'structural condition' which is exploited to simplify bookkeeping of the neighbour graph. However, bisection refinement places certain restrictions on the initial, coarsest grid. For a simply connected domain, a precise and useful criterion for the applicability of the described refinement scheme is formulated and proven.
In this paper, we present a novel rendering method which integrates reflective or refractive objects into a differential instant radiosity (DIR) framework usable for mixed-reality (MR) applications. ...This kind of objects are very special from the light interaction point of view, as they reflect and refract incident rays. Therefore they may cause high-frequency lighting effects known as caustics. Using instant-radiosity (IR) methods to approximate these high-frequency lighting effects would require a large amount of virtual point lights (VPLs) and is therefore not desirable due to real-time constraints. Instead, our approach combines differential instant radiosity with three other methods. One method handles more accurate reflections compared to simple cubemaps by using impostors. Another method is able to calculate two refractions in real-time, and the third method uses small quads to create caustic effects. Our proposed method replaces parts in light paths that belong to reflective or refractive objects using these three methods and thus tightly integrates into DIR. In contrast to previous methods which introduce reflective or refractive objects into MR scenarios, our method produces caustics that also emit additional indirect light. The method runs at real-time frame rates, and the results show that reflective and refractive objects with caustics improve the overall impression for MR scenarios.
We study the impact of sellers’ reserve prices on transfer prices in online auctions of virtual football players at Hattrick.org. We introduce an empirical model that distinguishes between two ...separate effects from public reserve prices: (1) a mechanical effect, which is driven by the design of the English auction and (2) a psychological reference-dependence effect through reserve prices serving as reference points. The psychological effect has recently been introduced in behavioral models of situations where agents are uncertain about their own willingness-to-pay, while the mechanical effect is well captured by standard auction theory. Controlling for censoring when players are not sold, both effects are observed. Once we account for the potential endogeneity of reserve prices, however, we do not find evidence for reference dependence in Hattrick auctions.
We study the optimal observability of the tax base within the standard linear income tax problem, where observability is determined by the government's investment into the accurate measurement of the ...tax base.
This article presents a rich context of information for interpreting Stanford Achievement Test scores and for describing the achievement of deaf and hard-of-hearing students. The publisher's national ...norming of the Stanford Achievement Test provides a context of actual performance of hearing students. The publisher's Performance Standards provide a context of expectations for hearing students as determined by a panel of experts. The Gallaudet Research Institute's norming of the test on a national sample of deaf and hard-of-hearing students provides a context of test performance by this special population. A smaller subsample of the deaf and hardof-hearing students who take the same test levels as hearing students provides an additional reference group with respect to the Performance Standards. Information from these sources is brought together into two graphical contexts to address these questions: Can the normative data from the publisher's national standardization of the test with hearing students, and the normative data from the GRI's national norming of the test with deaf and hard-of-hearing students provide a useful context for the interpretation of individual test scores? Can they provide a useful way to examine achievement of groups of students? Can the new Performance Standards defined by the test publisher offer a useful context for test score interpretation for high-achieving deaf and hardof-hearing students?
The 2016 Mars Utah Rover Field Investigation (MURFI) was a Mars rover field trial run by the UK Space Agency in association with the Canadian Space Agency's 2015/2016 Mars Sample Return Analogue ...Deployment mission. MURFI had over 50 participants from 15 different institutions around the UK and abroad. The objectives of MURFI were to develop experience and leadership within the UK in running future rover field trials; to prepare the UK planetary community for involvement in the European Space Agency/Roscosmos ExoMars 2020 rover mission; and to assess how ExoMars operations may differ from previous rover missions. Hence, the wider MURFI trial included a ten-day (or ten-‘sol’) ExoMars rover-like simulation. This comprised an operations team and control centre in the UK, and a rover platform in Utah, equipped with instruments to emulate the ExoMars rovers remote sensing and analytical suite. The operations team operated in ‘blind mode’, where the only available data came from the rover instruments, and daily tactical planning was performed under strict time constraints to simulate real communications windows. The designated science goal of the MURFI ExoMars rover-like simulation was to locate in-situ bedrock, at a site suitable for sub-surface core-sampling, in order to detect signs of ancient life. Prior to “landing”, the only information available to the operations team was Mars-equivalent satellite remote sensing data, which were used for both geologic and hazard (e.g., slopes, loose soil) characterisation of the area. During each sol of the mission, the operations team sent driving instructions and imaging/analysis targeting commands, which were then enacted by the field team and rover-controllers in Utah. During the ten-sol mission, the rover drove over 100 m and obtained hundreds of images and supporting observations, allowing the operations team to build up geologic hypotheses for the local area and select possible drilling locations. On sol 9, the team obtained a subsurface core sample that was then analyzed by the Raman spectrometer. Following the conclusion of the ExoMars-like component of MURFI, the operations and field team came together to evaluate the successes and failures of the mission, and discuss lessons learnt for ExoMars rover and future field trials. Key outcomes relevant to ExoMars rover included a key recognition of the importance of field trials for (i) understanding how to operate the ExoMars rover instruments as a suite, (ii) building an operations planning team that can work well together under strict time-limited pressure, (iii) developing new processes and workflows relevant to the ExoMars rover, (iv) understanding the limits and benefits of satellite mapping and (v) practicing efficient geological interpretation of outcrops and landscapes from rover-based data, by comparing the outcomes of the simulated mission with post-trial, in-situ field observations. In addition, MURFI was perceived by all who participated as a vital learning experience, especially for early and mid-career members of the team, and also demonstrated the UK capability of implementing a large rover field trial. The lessons learnt from MURFI are therefore relevant both to ExoMars rover, and to future rover field trials.
•MURFI: a UK Space Agency Funded Mars Rover trial.•Field site in Utah, USA; Rover control centre in Harwell, UK.•Includes a 9-sol ExoMars Rover-like mission element.•ExoMars rover-like instrument suite and platform.•‘Lessons learnt’ relevant to future trials and future ExoMars Rover operations.
In this paper we present a prototype system for collaborative visual analysis of tunnel monitoring data. Remotely located analysts (e.g., geotechnical experts) explore a dynamic 3D scene either with ...conventional desktop setups or fully immersive with virtual reality headsets. They can inform peers about results and insights by creating a presentation with integrated storytelling mechanisms. The experience is based on a 3D scene of a construction site, featuring digital twins of tunnels as key elements, which are enhanced by geospatially anchored sensors. Animated visualizations show the progress of the construction and its effect on sensor values. A story is defined by choosing stations and timepoints in the 3D scene and adding narrations and additional media. Storytelling is a powerful method for asynchronous collaboration because it makes an analysis session more comprehensible and reproducible, thereby increases trust. Furthermore, it is also very effective for the training of apprentices.
This paper analyzes the relation between tax auditing and fiscal equalization in the context of fiscal competition. We incorporate a model of tax evasion by firms into a standard tax competition ...framework where regional governments use their audit rates as a strategic instrument to engage in fiscal competition. We compare the region’s choice of audit policies for three different cases: A scenario of unconfined competition without interregional transfers, a scenario with a gross revenue equalization (GRS) scheme and finally, a scenario with net revenue sharing (NRS), where not only the revenues from taxation but also the regions auditing costs are shared. Without regional transfers, fiscal competition leads to audit rates which are inefficiently low for revenue-maximizing governments. While in general GRS aggravates the inefficiency, NRS makes the decentralized choice of auditing policies more efficient. Copyright Springer Science + Business Media, Inc. 2005
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