Comparison of the Spectral Representation Method to Simulate Spatially Variable Ground Motions

The spectral representation method (SRM) is widely used when simulating spatially variable ground motions. It has mainly two formulas, i.e., the random amplitudes and the random phases formulas. There exist three methods for decomposing the cross spectral density matrix: Cholesky decomposition, eigen decomposition, and root decomposition. Therefore, there are six forms with respect to the different combinations of the simulation formulas and the decomposition methods. To provide researchers and engineers with the guidance on choosing simulation method, the six forms are systematically investigated from five aspects: the power intensity, response spectra, and stochastic error of auto/cross spectral density, Fourier spectra, and difference indexes for Fourier amplitudes and phases. Finally, we give the following advice: the characteristics of the ground motions simulated by the random amplitudes formula are independent of the decomposition method, while the characteristics of the ground motions simulated by random phases formula are dependent of the decomposition method. Furthermore, the root decomposition is strongly recommended when utilizing the random phases formula.     

隋唐长安城规划主题——皇权永祚的龟鼎之城

关于唐长安前身——隋大兴城的规划思想,以前很少谈论。其实隋宇文恺规划设计首都大兴城,除了按照传统体现天子尊贵的“九五”数字外,并创造性地在都城平面图中暗含若干代表鼎足的等边三角形,用以体现“定鼎”——掌握政权之意。同时,在都城中轴线南端——明德门外,埋置石龟,与鼎足结合表明“皇权永祚”。     

Basketry accessories: footwear,bags and fans in ancient Egypt

Ancient Egyptians had —by the New Kingdom— developed many basket making and matting techniques. These techniques were not only used for making all types and sizes of baskets and mats, but were also adopted for making other accessories such as bags, fans and different types of footwear, that seem to have been heavily used. Materials and techniques of nine objects consisting of 2 sandals, 2 shoes, 2 bags, 2 fans and a model of a mat at the Agricultural Museum in Giza were carefully studied.     

Formation processes of desiccated and carbonized plant remains – the identification of routine practice

The taphonomic or formation processes of desiccated and carbonized plant remains are reviewed and compared. Both types of assemblage frequently consist of material of mixed origin, but despite a high degree of mixing, the various routes of entry are still identifiable, and it is concluded that archaeological plant assemblages are more robust than often assumed. Case studies where the accurate identification of the formation processes has been critical are examined and guidelines on how to assess the formation processes are presented. It is argued that the coherence of archaeobotanical assemblages is due to the fact that they represent day-to-day routine behavioural practices. As these routine practices are socially and culturally structured, the identification of formation processes of plant remains can help identify social and cultural behaviour and changes therein.     

全面抗战前央地关系视域下的南京国民政府省制变革

全面抗战前南京国民政府省制变革是近代中国省制变革的一个重要历史阶段。这一时期,大体经历了南京国民政府初期的省区分治与权势平衡、二次北伐完成后关于省财权人事权和军事权的央地博弈与武力纷争、中原大战后集权与分治的微妙平衡三个阶段的演变。南京政府正常的省权制度变革无法有序展开,在体制内却只能依靠军事和战争手段解决。这是最下策之下策,而且无法真正有效解决省权过大问题。直到全面抗战前夕,省制变革一直成为牵引中国时局演化与社会变动的中枢和焦点问题。     

Shades of blue – cobalt-copper coloured blue glass from New Kingdom Egypt and the Mycenaean world: a matter of production or colourant source?

Cobalt blue glass has long now been recognised as characterised by a distinct compositional signature within the typical compositional range of Late Bronze Age glass. More recently, a copper-rich variation of cobalt blue glass has been seen throughout Egypt and the Mycenaean world. This paper discusses and defines this glass type based on trace elemental data, examines whether this lighter-shaded cobalt blue glass is a natural or an anthropogenic variant of cobalt blue glass, and identifies its likely production in Egypt. It investigates the role of this type of glass, particularly with regard to the distribution pattern and the significance of its prevalence in the Mycenaean mainland and the Aegean.     

Combined pollen and macrofossil data as a source for reconstructing mosaic patterns of the early medieval urban habitats – a case study from Gdańsk,N. Poland

Plant macrofossils, pollen, fungal spores and other non-pollen palynomorphs (NPPs), were analyzed in three archaeological exposures established in a small area in the oldest part of the historic city of Gdańsk. One of the aims was to investigate how precisely the combined pollen and macrofossil data may reflect the diversity of local habitats within an urban archaeological site and to compare the range of information obtained using each of the methods separately. The other aim of the study was to reconstruct the environmental conditions in the earliest occupied area of the historic centre of Gdańsk. The repeatable composition and, in many points, consistency among pollen and macrofossil data in all three profiles strongly suggest that the apparently biased structure of these fossil remains in fact reflects a mosaic pattern of the vegetation in the area of the site. The combined pollen and macrofossil data enabled separation of local elements from those transported to the site by different means. The results show that already at the beginning of the 12th c., the area was almost totally deforested, but up to the mid-13th c. the settlement organization was still relatively loose, resembling a rather rural structure with well-developed ruderal plant communities and patches of semi-natural vegetation. At the coring area, strongly eutrophic riparian vegetation was bordering patches of dry grassland on a sandy holm. The large proportion of pollen of various entomophilous plants mostly from meadows and pastures is explained as a result of the presence of dung, as confirmed by the abundances of coprophilous fungal spores. The study indicates that parallel pollen and macrofossil analysis is essential for correct interpretation of fossil assemblages. Application of both methods enables broadening of the range of remains representing various organisms and obtaining more precise tools for environmental reconstruction and better understanding of the taphonomic processes at the archaeological site.     

Symbol and power: the Dalai Lama as a charismatic leader

This article originated in a brief but inspiring analysis by Margaret Nowak. Nowak used Sherry Ortner's concept of ‘summarising symbol’ to imply that, much the same way as the American flag was the epitome of the United States to each and every American, the Dalai Lama encompasses everything Tibetan to the Tibetan people. What does this comparison say about the Dalai Lama? I examine the relationship between symbol, power and charisma with Tenzin Gyatso, the current Dalai Lama, as a case in point. With exile, there has been a shift in the symbolic importance of the Dalai Lama, both as a man and as an institution, from a symbol of Tibet and Tibetan Buddhism to a symbol of the Tibetan cause and, more generally, to a symbol of Buddhism in the world. These changes have given Tenzin Gyatso a new authority in the Tibetan community: he is now the unique and unquestioned leader of the Tibetan cause in the world. I discuss the problems that occur when a symbol is also a man and a leader, as well as the solutions proposed, at a moment when the Tibetan community in exile is experiencing democratisation.     

从9种核心期刊的文献计量分析看核技术在文物保护与考古中的应用

从9种核心期刊的文献计量统计分析入手,分析了不同期刊、不同具体核技术方法、不同年份核技术应用文献量的差别,研究了差别的原因.介绍了主要核技术具体方法的含义和在考古及文物保护工作中的作用.分析和数据表明,核技术在考古和文物保护领域更广泛地应用及提高年代测量精度是核技术应用的两个发展方向.     

Maximum Possible Ground Motion for Linear Structures

This article develops a method to generate ground motion time histories that maximize the response of a given linearly elastic structure. The root mean square (RMS) level of the input power spectral density (PSD) is used as a strong motion parameter. It is related to seismological data that is readily available. An empirical relation to estimate RMS value of the PSD from peak ground acceleration, magnitude, rupture distance, and shear wave velocity is derived from world-wide strong motion data. The ground motion is obtained by solving the inverse problem such that the structural response is maximized under the constraint of fixed value of RMS level of the input PSD enforced using a Lagrange multiplier. The proposed methodology is illustrated for a single-degree of freedom system, a six storey building and an earthen dam. It is shown that the critical PSD obtained in all the cases is a narrow band process resulting in stochastic resonance and not a Dirac-delta function with the entire energy of the system concentrated at its natural frequency. Moreover, the critical excitation samples generated using this critical PSD resembles actual earthquake acceleration time histories.