宁波智慧城管平台决策分析工具研究

基于物联网、云计算、大数据等信息技术的全面应用,宁波市智慧城管在巩固现有数字城管平台的同时推进了以SDSS为主导的决策分析系统的建设。本文介绍了SDSS决策分析系统的基本概念、框架和分类,探讨了宁波市智慧城管的SDSS的总体结构图,阐述了宁波智慧城管具体建设内容,最后对宁波市智慧城管的发展研究进行了总结和展望。     

Extinction curves expected in young galaxies

We investigate the extinction curves of young galaxies in which dust is supplied from Type II supernovae (SNe II) and/or pair instability supernovae (PISNe). We adopt Nozawa et al. (2003) for compositions and size distribution of grains formed in SNe II and PISNe. We find that the extinction curve is quite sensitive to internal metal mixing in supernovae (SNe). The extinction curves predicted from the mixed SNe are dominated by SiO₂ and are characterized by a steep rise from infrared to ultraviolet (UV). The dust from unmixed SNe shows a shallower extinction curve, because of the contribution from large-sized (∼0.1 μm) Si grains. However, the progenitor mass is important in unmixed SNe II: if the progenitor mass is smaller than  ∼20 M_⊙  , the extinction curve is flat in UV; otherwise, the extinction curve rises towards the short wavelength. The extinction curve observed in a high-redshift quasar  ( z = 6.2)  favours the dust production by unmixed SNe II. We also provide some useful observational quantities, so that our model might be compared with future high- z extinction curves.     

The long-period AM CVn star SDSS J155252.48+32 0150.9

The Sloan Digital Sky Survey has been instrumental in obtaining a homogeneous sample of the rare AM CVn stars: mass-transferring binary white dwarfs. As part of a campaign of spectroscopic follow-up on candidate AM CVn stars from the Sloan Digital Sky Survey, we have obtained time-resolved spectra of the   g = 20.2  candidate SDSS J155252.48+320150.9 on the Very Large Telescope of the European Southern Observatory. We report an orbital period   P _orb= 3376.3 ± 0.3 s  , or 56.272 ± 0.005 min, based on an observed 'S-wave' in the helium emission lines of the spectra. This confirms the ultracompact nature of the binary. Despite its relative closeness to the orbital period minimum for hydrogen-rich donors, there is no evidence for hydrogen in the spectra. We thus classify SDSS J1552 as a new bona fide AM CVn star, with the second-longest orbital period after V396 Hya  ( P = 65.5 min)  . The continuum of SDSS J1552 is compatible with either a blackbody or helium atmosphere of   T _eff= 12 000–15 000 K  . If this represents the photosphere of the accreting white dwarf, as is expected, it puts the accretor at the upper end of the temperature range predicted by thermal evolution models. This suggests that SDSS J1552 consists of (or formerly consisted of) relatively high-mass components.     

The framework of a geospatial semantic web-based spatial decision support system for Digital Earth

Abstract

While significant progress has been made to implement the Digital Earth vision, current implementation only makes it easy to integrate and share spatial data from distributed sources and has limited capabilities to integrate data and models for simulating social and physical processes. To achieve effectiveness of decision-making using Digital Earth for understanding the Earth and its systems, new infrastructures that provide capabilities of computational simulation are needed. This paper proposed a framework of geospatial semantic web-based interoperable spatial decision support systems (SDSSs) to expand capabilities of the currently implemented infrastructure of Digital Earth. Main technologies applied in the framework such as heterogeneous ontology integration, ontology-based catalog service, and web service composition were introduced. We proposed a partition-refinement algorithm for ontology matching and integration, and an algorithm for web service discovery and composition. The proposed interoperable SDSS enables decision-makers to reuse and integrate geospatial data and geoprocessing resources from heterogeneous sources across the Internet. Based on the proposed framework, a prototype to assist in protective boundary delimitation for Lunan Stone Forest conservation was implemented to demonstrate how ontology-based web services and the services-oriented architecture can contribute to the development of interoperable SDSSs in support of Digital Earth for decision-making.     

Extinction curves flattened by reverse shocks in supernovae

We investigate the extinction curves of young galaxies in which dust is supplied from Type II supernovae (SNe II) and/or pair instability supernovae (PISNe). Since at high redshift ( z > 5), low-mass stars cannot be dominant sources for dust grains, SNe II and PISNe, whose progenitors are massive stars with short lifetimes, should govern the dust production. Here, we theoretically investigate the extinction curves of dust produced by SNe II and PISNe, taking into account reverse shock destruction induced by collision with ambient interstellar medium. We find that the extinction curve is sensitive to the ambient gas density around a SN, since the efficiency of reverse shock destruction strongly depends on it. The destruction is particularly efficient for small-sized grains, leading to a flat extinction curve in the optical and ultraviolet wavelengths. Such a large ambient density as   n _H≳ 1 cm⁻³  produces too flat an extinction curve to be consistent with the observed extinction curve for SDSS J1048+4637 at z = 6.2. Although the extinction curve is highly sensitive to the ambient density, the hypothesis that the dust is predominantly formed by SNe at z ∼ 6 is still allowed by the current observational constraints. For further quantification, the ambient density should be obtained by some other methods. Finally, we also discuss the importance of our results for observations of high- z galaxies, stressing a possibility of flat extinction curves.     

Correlation analysis of large-scale structure using data from the SDSS DR5 LRG catalog

Correlation properties of the large-scale structure of the distribution of luminous red galaxies are evaluated using data from Data Release 5 of the Sloan Digital Sky Survey. The correlations on small scales are characterized by the distribution of distances to the nearest neighboring galaxy ω(r). The conditional number density Γ(r) indicates a power law correlation with an exponent γ = 1.0±0.1 over scales of [1, 30] Mpc/h in redshift space. For larger scales of [30, 200] Mpc/h, a transition from a power law to a flat segment is observed. However, the presence of a flat segment in the estimated conditional density is only a necessary, but not sufficient, condition for homogeneity of a given sample. In particular, the flat segment may be caused by the presence of superlarge structures (such as have been discovered in the most recent ultra-deep COSMOS survey) which lead to a systematic shift in the estimated conditional number density. The behavior of the reduced two-point correlation function) ξ(r) is also discussed for scales of [1, 200] Mpc/h. Over small scales, where ξ(r) >> 1, the slopes of the reduced correlation function and the conditional number density are the same. __________ Translated from Astrofizika, Vol. 51, No. 3, pp. 393–408 (August 2008).     

空间辅助决策支持系统的应用模型及管理研究

应用建模是空间辅助决策支持系统有效管理和使用模型的基础。本文抽象了空间辅助决策应用模型的组成结构和建立过程,分析了空间辅助决策应用模型的特点;接着分基础空间模型库、基础非空间模型库、应用模型库、模型管理库四部分探讨了空间决策支持系统中应用模型的管理,最后给出了相应的建设性结果。     

水库移民GIS辅助决策支持系统的设计和实现

空间决策支持系统(Spatial Decision Support System SDSS)作为一个新兴科学技术领域,以地理信息系统(GIS)和决策支持系统(DSS)为基础,以解决生产实践问题为目标,目前已经被广泛应用于水利、交通、农业等行业。本文主要介绍应用SDSS数据和模型之间关系的思想设计和实现用于解决大型水库项目中涉及的移民安置处理问题的空间决策支持系统。系统中主要是以移民如何安置问题为基础来设计各种空间分析模型功能,其中与空间信息处理有关的几个模型主要有移民安置区选择,移民安置区环境容量分析,水库淹没损失赔偿以及移民安置区土地资源评价等问题。要解决这些生产实践问题需要对各种数据信息进行综合的宏观分析和深层次挖掘分析,结合专家知识设计可行的处理模型,并运用计算机技术和GIS技术加以实现。