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.     

'Nothing Can Ever Be the Case of 'Us' and 'Them' Again': Exploring the politics of difference through border pedagogy and student journal writing

Linda McDowell (1994) has called for styles of teaching which put into practice arguments about the 'politics of difference', which has become an increasingly central part of human geographical research. This paper draws on a number of years' experience of teaching an undergraduate course on multicultural historical geography, in which this was attempted. Here students were encouraged to get more involved in these debates, to take them more personally, and to develop 'situated knowledges' about the UK as a multicultural society. The approach to teaching, learning and assessment which made this possible was based on the principles of 'border pedagogy' and on students writing journals throughout the course which charted the development of their understandings of the materials they encountered.     

两种不同环境控制下砂岩类文物岩石材料剥落特征及形成机制差异性的研究

为了研究不同环境对砂岩类文物岩石材料劣化的影响和控制,本工作以北京西黄寺和柬埔寨吴哥遗址周萨神庙两种砂岩类文物岩石材料为研究对象,从砂岩表层剥落形态、物理性质、化学矿物成分及微观结构变异四个方面对剥落特征进行了系统论述,并从岩石特性和环境因素两方面对剥落形成机制进行了分析.研究结论认为周萨神庙砂岩表层剥落比西黄寺砂岩更严重,这是由于其材料本身特性略差、大气降雨作用和生物活动更频繁造成的.本工作的测试方法及剥落形成的机制可为类似研究提供参考.     

Study of a Ground-Motion Simulation Method using a Causality Relationship

The causality of natural ground motions is evaluated through statistical values for the phase difference. The causality is expressed in terms of the Hilbert transform relationship between the real and imaginary parts of the Fourier transform of the ground motion. We find that ground motions with a shorter duration have a higher degree of causality. Furthermore, we propose a ground-motion simulation algorithm that incorporates causality. The simulated ground motions, compatible with design response spectra, have almost the same spectrum conversion factors as those estimated from natural ground motions.     

空间地理规律对区域(中国)发展过程的影响

运用空间地理规律探讨历史区域的空间发展过程,在古代中国具有十分良好有利的客观条件。本文基于较大空间尺度和较长历史时限,针对区域地理诸多分异现象的发生和变化,系统阐述了这一规律的三个方面(纬度地带性规律、经度省性和垂直地带性规律),在不同区域或地带空间发展过程中突出的表现特点和影响形式。     

NDVI Variability in North East India

Abstract

The variability of the Normalized Difference Vegetation Index (NDVI) in north east India in response to rainfall and temperature was analysed using twice-monthly NOAA/AVHRR satellite imagery acquired during 1982–2002 from the GIMMS (Global Inventory Modeling and Mapping Studies) data-set. Corresponding rainfall and temperature estimates were extracted from the Climate Research Unit's CR TS 2.1 data-set for 34 study sites, chosen using the GLC 2000 land use categories. The selected sites represent nine land use categories under differing institutional frameworks. Results showed a weak linear relationship between the growing season rainfall and NDVI range when plotted in a scatter diagram. The negative correlation between NDVI and rainfall and temperature and NDVI in the study area was accentuated during the growing season and a one- and two-month lag for rainfall and temperature respectively was operating. A gain coefficient image to determine the temporal change in NDVI during the 21-year period indicated a consistent decline for much of the study area. Among the study sites those under state protection fared better than sites under other institutional frameworks. Along with rainfall and temperature, land use and institutional frameworks emerged as causative factors in the dynamics of vegetation greenness in north east India.     

良渚文化的聚落级差及城市萌芽

聚落级差是指聚落之间规模尺度与发展水平的差异。根据目前的考古资料,环太湖地区的聚落级差始自崧泽文化晚期,其扩大化过程在良渚文化中期达到顶点,聚落级差作为一种现象一直持续至良渚文化晚期。良渚遗址群反映出良渚文化中期聚落级差的极端化,已经超越了一般聚落遗存的范畴,是处于萌芽状态的城市。城市萌芽是环太湖地区聚落级差扩大程度的标志性结果,聚落级差扩大化过程本身也蕴含了城市萌芽的催生力量。     

Trans/national knowledge production through difference: dilemmas of doing research on veiling in Amman,Jordan

Abstract

This article examines some dilemmas I experienced while doing research on fashionable veiling in Amman, Jordan. My fieldwork experience and the knowledge I co-produced with the participants were shaped by each layer of my identity as a Jordanian, Muslim, non-veiled woman, with a particular classed, spatialized Ammani heritage and affiliation with western feminist academia. The article engages with the implications my positionality had on my insider-outsider status and the knowledge the participants and I co-produced. I argue that the research setting, while fraught with difference, constituted a site for transnational solidarity and knowledge production. The participants and I had divergent understandings of, and aspirations for, Jordanian Muslim femininity shaped by our varying positions within the Global North-Global South. I argue that we practiced solidarity by collaborating and co-constructing a transnational site to unpack and defend their viability. I found that our collaboration was not fuelled by a shared sense of injustice and did not produce a shared outlook on Islam, Jordanianness or femininity. Rather, it created a site where we were able to emphasize our divergent sense of these paradigms as women positioned differently within the trans/national, cultural, and religious spaces we shared.