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Using Coloured Petri Nets for design of parallel raytracing environment  [PDF]
Stefan Korecko,Branislav Sobota
Computer Science , 2010,
Abstract: This paper deals with the parallel raytracing part of virtual-reality system PROLAND, developed at the home institution of authors. It describes an actual implementation of the raytracing part and introduces a Coloured Petri Nets model of the implementation. The model is used for an evaluation of the implementation by means of simulation-based performance analysis and also forms the basis for future improvements of its parallelization strategy.
Raytracing simulations of coupled dark energy models  [PDF]
Francesco Pace,Marco Baldi,Lauro Moscardini,David Bacon,Robert Crittenden
Physics , 2014, DOI: 10.1093/mnras/stu2513
Abstract: Dark matter and dark energy are usually assumed to couple only gravitationally. An extension to this picture is to model dark energy as a scalar field coupled directly to cold dark matter. This coupling leads to new physical effects, such as a fifth-force and a time-dependent dark matter particle mass. In this work we examine the impact that coupling has on weak lensing statistics by constructing realistic simulated weak-lensing maps using raytracing techniques through N-body cosmological simulations. We construct maps for different lensing quantities, covering a range of scales from a few arcminutes to several degrees. The concordance $\Lambda$CDM model is compared to different coupled dark energy models, described either by an exponential scalar field potential (standard coupled dark energy scenario) or by a SUGRA potential (bouncing model). We analyse several statistical quantities and our results, with sources at low redshifts are largely consistent with previous work on CMB lensing by Carbone et al., 2013. The most significant differences from the $\Lambda$CDM model are due to the enhanced growth of the perturbations and to the effective friction term in non-linear dynamics. For the most extreme models, we see differences in the power spectra up to 40% compared to the $\Lambda$CDM model. The different time evolution of the linear matter overdensity can account for most of the differences, but when controlling for this using a $\Lambda$CDM model having the same normalization, the overall signal is smaller due to the effect of the friction term appearing in the equation of motion for dark matter particles.
3D raytracing through homogeneous anisotropic media with smooth interfaces
Costa, Jessé;Schoenberg, Michael;Urban, Jaime;
Revista Brasileira de Geofísica , 2002, DOI: 10.1590/S0102-261X2002000300003
Abstract: two-point raytracing problem is solved for events in a piecewise homogeneous and laterally varying 3d anisotropic media by continuation techniques. in conjunction with the shooting method the algorithm can be used for computation of qp, qs1, and qs2 events. the algorithm has the same performance and robustness as previous implementations of the continuation method for tracing rays in isotropic models. routines based on our algorithm have several useful applications. first, an efficient forward problem solver for traveltime inversion of elastic parameters in the presence of anisotropy. second, newton-raphson iterations during two-point raytracing produce wavefront attributes, slowness and wavefront curvature. these attributes allows the computation of geometrical spreading and second order approximations for traveltimes. therefore it can be used to investigate the effects of anisotropy on crs, in simple velocity models.
二迭纪  [PDF]
莫杰
地质与勘探 , 1980,
Abstract: 二迭纪(Permian)的名字来自俄罗斯北部贝尔姆省的名称,因为那里的二迭纪地层特别发育.其两分的由来是因为德国这个纪的地层明显地分为上下两部分而得名.世界二迭系(1841年莫迪逊确立了二迭系.1900年巴黎国际地质会议尚未承认二迭系,现在一般都承认了)标准剖面最初建立在西乌拉尔贝尔姆〔狭义的萨克马尔组(Sakmarian)〕,后在美国得克萨斯又建立一条剖面.这两条标准剖面的上部均为含盐建造,化石稀少,远没有我国二迭系剖面完整、
不同时期追氮对冬小麦植株氮素积累及转运特性的影响  [PDF]
马冬云, 郭天财*, 岳艳军, 宋 晓, 朱云集, 王晨阳, 王永华
植物营养与肥料学报 , 2009, DOI: 10.11674/zwyf.2009.0203
Abstract: 采用盆栽和大田相结合,并应用15N示踪技术,研究了不同时期追氮对两个不同穗型冬小麦品种植株氮素积累及转运特性的影响。结果表明,成熟期小麦植株各部位氮素积累量和分配比例均表现为子粒>茎鞘+叶>根系或颖壳+穗轴;子粒中氮素积累量以拔节期追氮处理最高,氮素在子粒中的分配比例以抽穗期追氮最高,在根系中的分配比例则以全部底施处理最高。小麦植株吸收追施15N的比例为16.45%~26.6%,兰考矮早八和豫麦49-198分别以返青期追氮和拔节期追氮吸收的比例最高;子粒中氮素来自15N的比例均以返青期追氮最高,分别为27.16%和22.20%,但和拔节期追氮处理差异不显著。随着追氮时期推迟,氮的花后同化量、花后贡献率增加,而花前贡献率呈下降趋势;全氮对子粒贡献率表现为花前转运的贡献大于花后同化的贡献,但抽穗期追氮处理中,15N对子粒的贡献率表现为花后同化率大于花前转运贡献率。综合考虑子粒产量、蛋白质含量以拔节期追氮较为合适。
四狗追戏问题的其他解法  [PDF]
朱晨
力学与实践 , 2000, DOI: 10.6052/1000-0992-f2000-058
Abstract: 本文通过直角坐标法及极坐标法求解四狗追戏问题.
A method of shortest path raytracing by iterative optimization
迭代优化的网络最短路径射线追踪方法研究

LU Bin,ZHOU Li-Fa,KONG Xing-Wu,BAI Bin,
鲁彬

地球物理学进展 , 2009,
Abstract: The shortest path raytracing algorithm in networks is widely applied to calculate scismic ray paths and traveltimes, in which the beelines between network nodes are used to approximate the ray paths. When using a few nodes the ray usually follows a zig-zag path that is longer than the real raypath, and the calculated traveltime at a receiver is also larger than the real one. To solve this problem, we develop a shortest path raytracing by iterative optimization. We use the iterative algorithm to optimize ray path to overcome the weakness of the conventional networks algorithm, so the precision of calculated minimum traveltimes and the raypaths are improved greatly.
Simulasi Pengaruh Ukuran Partikel terhadap Sifat Luminisensi Partikel YAG:Ce3+ Akibat Eksitasi Cahaya Biru dengan Model Raytracing
D Anggoro,F Faizal,B M Wibawa,I M Joni
Jurnal Nanosains & Nanoteknologi , 2009,
Abstract: Sifat luminisensi partikel Y2Al2O5:Ce3+ (YAG:Ce3+) dengan berbagai ukuran telah dipelajari dengan pemodelan raytracing menggunakan sumber pembangkit emisi berupa cahaya biru ( = 450 nm). Variabel-variabel yang bersifat acak dalam model raytracing, didekati dengan metode Monte Carlo. Hasil simulasi menunjukan bahwa pengaruh ukuran partikel sangat signifikan dalam penentuan cahaya LED. Emisi cahaya hasil simulasi menunjukan kesesuaian kualitatif dengan spektrum emisi yang diperoleh melalui eksperimen.
混凝土迭合梁的极限强度  [PDF]
皮永林
武汉理工大学学报 , 1982,
Abstract: ?本文分析了在强度极限状态下迭合梁截面上的应力和应变分布特点,根据平截面假定研究了迭合梁极限强度的计算方法,探讨了迭合梁超筋破坏和适筋破坏之间的界限值。
对交迭任务记忆的实验研究(Ⅱ)
方俐洛,高晶
心理学报 , 1990,
Abstract: 对交迭记忆任务的实验室模拟实验结果表明:(1)任务交迭类型、交迭任务数和任务呈现间隔时间都是影响交迭记忆业绩的因素。交迭记忆业绩随任务交迭类型的复杂程度提高而降低,随呈现间隔时间的延长而提高;在复式交迭类型中,随交迭任务数的增多而降低。从而说明了时间繁忙和信息加工强度是心理负荷的两个因素。(2)据实验结果求出了在本实验情境下的交迭记忆曲线公式。
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