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2022 ◽  
Vol 2 ◽  
Author(s):  
Lingwei Tong ◽  
Robert W. Lindeman ◽  
Holger Regenbrecht

Content creators have been trying to produce engaging and enjoyable Cinematic Virtual Reality (CVR) experiences using immersive media such as 360-degree videos. However, a complete and flexible framework, like the filmmaking grammar toolbox for film directors, is missing for creators working on CVR, especially those working on CVR storytelling with viewer interactions. Researchers and creators widely acknowledge that a viewer-centered story design and a viewer’s intention to interact are two intrinsic characteristics of CVR storytelling. In this paper, we stand on that common ground and propose Adaptive Playback Control (APC) as a set of guidelines to assist content creators in making design decisions about the story structure and viewer interaction implementation during production. Instead of looking at everything CVR covers, we set constraints to focus only at cultural heritage oriented content using a guided-tour style. We further choose two vital elements for interactive CVR: the narrative progression (director vs. viewer control) and visibility of viewer interaction (implicit vs. explicit) as the main topics at this stage. We conducted a user study to evaluate four variants by combining these two elements, and measured the levels of engagement, enjoyment, usability, and memory performance. One of our findings is that there were no differences in the objective results. Combining objective data with observations of the participants’ behavior we provide guidelines as a starting point for the application of the APC framework. Creators need to choose if the viewer will have control over narrative progression and the visibility of interaction based on whether the purpose of a piece is to invoke emotional resonance or promote efficient transfer of knowledge. Also, creators need to consider the viewer’s natural tendency to explore and provide extra incentives to invoke exploratory behaviors in viewers when adding interactive elements. We recommend more viewer control for projects aiming at viewer’s participation and agency, but more director control for projects focusing on education and training. Explicit (vs. implicit) control will also yield higher levels of engagement and enjoyment if the viewer’s uncertainty of interaction consequences can be relieved.


2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
◽  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  

Abstract Jet fragmentation transverse momentum (jT) distributions are measured in proton-proton (pp) and proton-lead (p-Pb) collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5.02 TeV with the ALICE experiment at the LHC. Jets are reconstructed with the ALICE tracking detectors and electromagnetic calorimeter using the anti-kT algorithm with resolution parameter R = 0.4 in the pseudorapidity range |η| < 0.25. The jT values are calculated for charged particles inside a fixed cone with a radius R = 0.4 around the reconstructed jet axis. The measured jT distributions are compared with a variety of parton-shower models. Herwig and Pythia 8 based models describe the data well for the higher jT region, while they underestimate the lower jT region. The jT distributions are further characterised by fitting them with a function composed of an inverse gamma function for higher jT values (called the “wide component”), related to the perturbative component of the fragmentation process, and with a Gaussian for lower jT values (called the “narrow component”), predominantly connected to the hadronisation process. The width of the Gaussian has only a weak dependence on jet transverse momentum, while that of the inverse gamma function increases with increasing jet transverse momentum. For the narrow component, the measured trends are successfully described by all models except for Herwig. For the wide component, Herwig and PYTHIA 8 based models slightly underestimate the data for the higher jet transverse momentum region. These measurements set constraints on models of jet fragmentation and hadronisation.


Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 243
Author(s):  
David Gobrecht ◽  
Jan Philip Sindel ◽  
Helena Lecoq-Molinos ◽  
Leen Decin

Stellar dust grains are predominantly composed of mineralic, anorganic material forming in the circumstellar envelopes of oxygen-rich AGB stars. However, the initial stage of the dust synthesis, or its nucleation, is not well understood. In particular, the chemical nature of the nucleating species, represented by molecular clusters, is uncertain. We investigated the vertical and adiabatic ionization energies of four different metal-oxide clusters by means of density functional theory. They included clusters of magnesia (MgO)n, silicon monoxide (SiO)n, alumina (Al2O3)n, and titania (TiO2)n with stoichiometric sizes of n = 1–8. The magnesia, alumina, and titania clusters showed relatively little variation in their ionization energies with respect to the cluster size n: 7.1–8.2 eV for (MgO)n, from 8.9–10.0 eV for (Al2O3)n, and 9.3–10.5 eV for (TiO2)n. In contrast, the (SiO)n ionization energies decrease with size n, starting from 11.5 eV for n = 1, and decreasing to 6.6 eV for n = 8. Therefore, we set constraints on the stability limit for neutral metal-oxide clusters to persist ionization through radiation or high temperatures and for the nucleation to proceed via neutral–neutral reactions.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Juan Carlos Criado ◽  
Abdelhak Djouadi ◽  
Manuel Pérez-Victoria ◽  
José Santiago

Abstract We present an effective field theory describing the relevant interactions of the Standard Model with an electrically neutral particle that can account for the dark matter in the Universe. The possible mediators of these interactions are assumed to be heavy. The dark matter candidates that we consider have spin 0, 1/2 or 1, belong to an electroweak multiplet with arbitrary isospin and hypercharge and their stability at cosmological scales is guaranteed by imposing a ℤ2 symmetry. We present the most general framework for describing the interaction of the dark matter with standard particles, and construct a general non-redundant basis of the gauge-invariant operators up to dimension six. The basis includes multiplets with non-vanishing hypercharge, which can also be viable DM candidates. We give two examples illustrating the phenomenological use of such a general effective framework. First, we consider the case of a scalar singlet, provide convenient semi-analytical expressions for the relevant dark matter observables, use present experimental data to set constraints on the Wilson coefficients of the operators, and show how the interplay of different operators can open new allowed windows in the parameter space of the model. Then we study the case of a lepton isodoublet, which involves coannihilation processes, and we discuss the impact of the operators on the particle mass splitting and direct detection cross sections. These examples highlight the importance of the contribution of the various non-renormalizable operators, which can even dominate over the gauge interactions in certain cases.


Author(s):  
Louise Rebecca ◽  
C Sivaram ◽  
Arun Kenath

Although the presence of dark energy is well established from various observations, its true nature is still not well understood. The cosmological constant term seems to be the preferred candidate. In earlier work we had a constant cosmological constant term to limit the sizes of large-scale structures at lower redshifts. In this work, we extend this to large scale structures at higher redshifts. Here we invoke a time varying cosmological constant to set constraints on sizes of galaxies at high redshifts and see that they are consistent with their observed sizes. The time-varying cosmological constant also provides a possible solution to the puzzle of structure formation of large disk galaxies (like the Wolfe disk) observed at very early stages of the Universe. Future observations of galaxies at even higher redshifts could support our approach.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1814
Author(s):  
An-Di Tang ◽  
Tong Han ◽  
Huan Zhou ◽  
Lei Xie

The unmanned aerial vehicle (UAV) path planning problem is a type of complex multi-constraint optimization problem that requires a reasonable mathematical model and an efficient path planning algorithm. In this paper, the fitness function including fuel consumption cost, altitude cost, and threat cost is established. There are also four set constraints including maximum flight distance, minimum flight altitude, maximum turn angle, and maximum climb angle. The constrained optimization problem is transformed into an unconstrained optimization problem by using the penalty function introduced. To solve the model, a multiple population hybrid equilibrium optimizer (MHEO) is proposed. Firstly, the population is divided into three subpopulations based on fitness and different strategies are executed separately. Secondly, a Gaussian distribution estimation strategy is introduced to enhance the performance of MHEO by using the dominant information of the populations to guide the population evolution. The equilibrium pool is adjusted to enhance population diversity. Furthermore, the Lévy flight strategy and the inferior solution shift strategy are used to help the algorithm get rid of stagnation. The CEC2017 test suite was used to evaluate the performance of MHEO, and the results show that MHEO has a faster convergence speed and better convergence accuracy compared to the comparison algorithms. The path planning simulation experiments show that MHEO can steadily and efficiently plan flight paths that satisfy the constraints, proving the superiority of the MHEO algorithm while verifying the feasibility of the path planning model.


2021 ◽  
Author(s):  
John Pernet-Fisher ◽  
Margaret Hartley ◽  
Kathrine Joy

&lt;p&gt;Metamorphic rocks on the Moon are an important yet under-studied suite of lunar lithologies that have been identified in the Apollo and lunar meteorite collections [1]. These rocks, with granoblastic textures, are generally referred to as granulites; however, unlike their terrestrial counterparts, they are considered to represent the products of only high-temperature (&gt; 1000 &lt;sup&gt;o&lt;/sup&gt;C) thermal metamorphism that completely re-crystallised their protolith(s). Lunar granulites are commonly sub-divided into two main compositional groups related to their protolith lithologies. The Fe-granulites, found at most Apollo landing sites, are generally accepted to derive from metamorphosed plagioclase-rich igneous cumulates, termed the ferroan anorthosite (FAN) suite. The FAN suite are important lithologies as they represent products of the primary lunar crust. The Mg-granulites are found mostly at the Apollo 16 landing site and within lunar meteorite samples; the protolith(s) of this latter group is not well understood [2]. &amp;#160;Early studies have linked the protolith to secondary magmatic intrusions into the primary anorthositic crust (termed the Mg-suite); however, recent studies have tentatively connected the protolith to a Mg-rich variation of the primary crustal plagioclase cumulates (termed the MAN suite). The occurrence of MANs is controversial, it is unclear how the MAN suite fits into canonical lunar crustal formation models [3]. To investigate the protoliths of the granulite suites, we report in situ trace- and minor-element abundances for olivine and pyroxene grains within Fe- and Mg-granulites, determined by LA-ICP-MS and EPMA respectively. Trace-element data presented here indicate that the Mg-granulites are compositionally similar to the MAN suite. Furthermore, by comparing plagioclase trace-element data with peak metamorphic temperatures (calculated using two-pyroxene thermometers [4]), we find no relationship between metamorphic temperature and diagnostic trace-element signatures suggesting that both granulite suites experienced similar thermal metamorphic conditions. Additionally, we estimate the duration of metamorphic heating using experimentally derived diffusion rates of minor elements in minerals, &amp;#160;(such as Ca in olivine [5]). Both the calculated cooling rates and peak metamorphic temperatures can set constraints on the metamorphic heat source responsible for thermally annealing the Fe- and Mg-granulites. Specifically, we are able to assess whether the granulites formed as a result of shallow (&lt;1 km) burial of the protolith by impact melt sheets or hot, impact-generated fall-back breccias [6]; or deep (&gt; 1km) contact metamorphism of the protolith due to the emplacement of magma chambers or upwelling plutons within the lunar crust [7].&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;[1] Lindstrom &amp; Lindstrom, 1986, JGR, 91(B4), 263-276 [2] Treiman et al. 2010. MaPS, 45, 163-180. [3] Gross et al. 2014, EPSL, 388, 318-328. [4] Brey &amp; K&amp;#246;hler, 1990, J Pet, 31, 1353-1378. [5] Dohmen et al, 2007, PCM, 34, 389-407. [6] Cushing et al. 1999, MaPS, 34, 185-195. [7] Hudgins et al. 2011, Am Min, 96, 1673-1685.&lt;/p&gt;


2021 ◽  
Vol 6 (1) ◽  
pp. 114-118
Author(s):  
Stanley I. Okafor ◽  
Azubuike H. Amadi ◽  
Mobolaji A. Abegunde

This project uses production data to generate well-specific correlations for GLR, BSW and sand concentration which are used for predictions. A software has been developed to effect a smart control algorithm. This results in a bean up or bean down operation depending on the current flowing conditions and constraints. Excel programming environment was used to write a code that constantly takes in measured data points, models the behavior of the individual data sets with bean size and controls the choke if the parameters of interest go above a predetermined cut-off. The software was also equipped with an inverse matrix solving algorithm that enables it to determine the choke performance constants for any set of initialization data. A set of data from field X were supplied and the choke performance constants; A, B, C, D and E, were found to be 10, 0.546, 0.0, 1.89 and 1.0 respectively. In addition to that, data from subsequent production operations were entered and the software was able to control the choke size to ensure that production stays below set constraints of 500, 80 and 10 in field units for GLR, BSW and sand concentration respectively. From this, it can be concluded that the software can effectively maintain the production of unwanted well effluents below their cut-offs, thereby improving oil production and the overall Net Profit Value (NPV) of a project.


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