1,120 research outputs found
On the estimation of integrated covariance matrices of high dimensional diffusion processes
We consider the estimation of integrated covariance (ICV) matrices of high
dimensional diffusion processes based on high frequency observations. We start
by studying the most commonly used estimator, the realized covariance (RCV)
matrix. We show that in the high dimensional case when the dimension and
the observation frequency grow in the same rate, the limiting spectral
distribution (LSD) of RCV depends on the covolatility process not only through
the targeting ICV, but also on how the covolatility process varies in time. We
establish a Mar\v{c}enko--Pastur type theorem for weighted sample covariance
matrices, based on which we obtain a Mar\v{c}enko--Pastur type theorem for RCV
for a class of diffusion processes. The results explicitly
demonstrate how the time variability of the covolatility process affects the
LSD of RCV. We further propose an alternative estimator, the time-variation
adjusted realized covariance (TVARCV) matrix. We show that for processes in
class , the TVARCV possesses the desirable property that its LSD
depends solely on that of the targeting ICV through the Mar\v{c}enko--Pastur
equation, and hence, in particular, the TVARCV can be used to recover the
empirical spectral distribution of the ICV by using existing algorithms.Comment: Published in at http://dx.doi.org/10.1214/11-AOS939 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Statistical Properties of Microstructure Noise
We study the estimation of moments and joint moments of microstructure noise.
Estimators of arbitrary order of (joint) moments are provided, for which we
establish consistency as well as central limit theorems. In particular, we
provide estimators of auto-covariances and auto-correlations of the noise.
Simulation studies demonstrate excellent performance of our estimators even in
the presence of jumps and irregular observation times. Empirical studies reveal
(moderate) positive auto-correlation of the noise for the stocks tested
The “Useless” Sustainability: Chinese and American Discourses of Eco-Fashion and the Utilitarian Fantasy
What can China bring to the international dialog of eco-fashion? How can Chinese ways of imagining sustainability teach us new ways to think about fashion, ethics, and environment? This paper focuses on the design practice and philosophy of China’s first-generation eco-fashion designer, Ma Ke, and places her work in juxtaposition with the mainstream discourses of eco-fashion in the US. Adopting a Lacanian psychoanalytic approach, my analysis identifies an ideology of utilitarianism in the US discourse of eco-fashion that aims to maximize resource usage and minimize pollution and waste. Ma Ke’swork, by contrast, criticizes utilitarianism and proposes to conceiveour ethical relationship with the material world not through utility, butthrough memory and history. She portrays textiles as a humble medium that records the past, while the traces left from the past constitute the most seductive part of our clothes. Ma Ke’s work, I argue, offers a critique of the dominant ideologies in Western eco-fashion and helps us rethink the relationship between fashion, environment, and the ethics of consumption.
Correction of "Cloud Removal By Fusing Multi-Source and Multi-Temporal Images"
Remote sensing images often suffer from cloud cover. Cloud removal is
required in many applications of remote sensing images. Multitemporal-based
methods are popular and effective to cope with thick clouds. This paper
contributes to a summarization and experimental comparation of the existing
multitemporal-based methods. Furthermore, we propose a spatiotemporal-fusion
with poisson-adjustment method to fuse multi-sensor and multi-temporal images
for cloud removal. The experimental results show that the proposed method has
potential to address the problem of accuracy reduction of cloud removal in
multi-temporal images with significant changes.Comment: This is a correction version of the accepted IGARSS 2017 conference
pape
Chinese Culture Overseas Exchange and Spread Under the Context of Cross-Cultural Perspective
The rapid development of economy and the rise of international politics caused the “China craze” of the international community, and is also an opportunity to spread Chinese culture overseas. Chinese culture has long been in the passive position of “the other construction”, the communication mode will make China lose the ownership of cultural exchange, and then make the culture in the “edge” status. In cross-cultural communication, how to play the government power, through the artifacts, the media and non-governmental organizations to build a complete system of cultural transmission, cultural communication to realize the rationality and validity, give play to its dominant position in Chinese cultural exchange, get the real “image of China” and “voice of China”, is the main direction of the current Chinese culture propagation. Actively integrating into the world culture system, to realize the combination of Chinese culture and the world civilization, not only is the symbol of country cultural confidence and expression, and contribute to world peace and cultural development
The Development of Jingdezhen in the View of Cultural Innovation
Jingdezhen porcelain is famous all over the world. During the development of ceramics, with continuous cultural innovation and technological progress, it created the legends of the city development. But in modern times, the development of Jingdezhen was in trouble. How to reshape the glorious city and realize the sustainable development of the economy? This paper, from the perspective of cultural innovation, Jingdezhen in space, time, technology, brand many dimensions, Jingde town development and urban construction are put forward for sustainable development train of thought.Key words: Cultural innovation; Jingdezhen; Ceramics; Urban developmen
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