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Search Results: 1 - 10 of 28457 matches for " JIA Tao "
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Existence of Solutions to a Generalized System  [PDF]
Yali Zhao, Lin Xing, Jia Tao
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.36077
Abstract: In this paper, we introduce a generalized system (for short, GS) in real Banach spaces. Using Brouwer’s fixed point theorem, we establish some existence theorems for the generalized system without monotonicity. Further, we extend the concept of C-strong pseudomonotonicity and extend Minty’s lemma for the generalized system. And using the Minty lemma and KKM-Fan lemma, we establish an existence theorem for the generalized system with monotonicity in real reflexive Banach spaces. As the continuation of existing studies, our paper present a series of extended results based on existing corresponding results.
Construction of Cross-Cultural Identity by Language Choice and Linguistic Practice: A Case-Study of Mixed Hong Kong-Mainland Identity in University Contexts  [PDF]
Tao Gong, Lan Shuai, Jia Liu
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.33028
Abstract:

Studying relations between language and speaker’s identity is an interdisciplinary field that involves intersections among language, culture, and society. By examining the language choice and linguistic practice, especially code-mixing and code-switching, of the Mainland China students who are studying in universities of Hong Kong, we reveal a mixed Hong Kong-Mainland identity in these students: those who hold a Mainland-oriented identity tend to have a Putonghua-dominated language choice and linguistic practice, whereas those who embrace a Hong Kong-oriented identity tend to prefer a Cantonese-dominated choice and practice. This mixed identity helps better conceive the social image of Mainland immigrants in Hong Kong and discuss the cross-cultural identity formed by linguistic practice.

Exploring Human Activity Patterns Using Taxicab Static Points
Tao Jia,Bin Jiang
ISPRS International Journal of Geo-Information , 2012, DOI: 10.3390/ijgi1010089
Abstract: This paper explores the patterns of human activities within a geographical space by adopting the taxicab static points which refer to the locations with zero speed along the tracking trajectory. We report the findings from both aggregated and individual aspects. Results from the aggregated level indicate the following: (1) Human activities exhibit an obvious regularity in time, for example, there is a burst of activity during weekend nights and a lull during the week. (2) They show a remarkable spatial drifting pattern, which strengthens our understanding of the activities in any given place. (3) Activities are heterogeneous in space irrespective of their drifting with time. These aggregated results not only help in city planning, but also facilitate traffic control and management. On the other hand, investigations on an individual level suggest that (4) activities witnessed by one taxicab will have different temporal regularity to another, and (5) each regularity implies a high level of prediction with low entropy by applying the Lempel-Ziv algorithm.
A mass transfer model for predicting emission of the volatile organic compounds in wet building materials
Tao Zhang,Li Jia
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0322-5
Abstract: A new mass transfer model is developped to predict the volatile organic compounds (VOCs) from fresh wet building materials. The dry section of wet materials during the process of VOC emission from wet building materials is considered in this new model, differing from the mass transfer-based models in other literatures. The mechanism of effect of saturated vapor pressure on the surface of wet building materials in the process of VOC emission is discussed. The concentration of total volatile organic compounds (TVOC) in the building materials gradually decreases as the emission of VOCs begins, and the vapor pressure of VOCs on the surface of wet building materials decreases in the case of newly wet building materials. To ensure the partial pressure of VOCs on the surface of wet building materials to be saturated vapor pressure, the interface of gas-wet layer is lowered, and a dry layer of no-volatile gases in the material is formed. Compared with the results obtained by VB model, CFD model and the experiment data, the results obtained by the present model agree well with the results obtained by CFD model and the experiment data. The present model is more accurate in predicting emission of VOC from wet building materials than VB model.
Zipf's Law for All the Natural Cities in the United States: A Geospatial Perspective
Bin Jiang,Tao Jia
Physics , 2010,
Abstract: This paper provides a new geospatial perspective on whether or not Zipf's law holds for all cities or for the largest cities in the United States using a massive dataset and its computing. A major problem around this issue is how to define cities or city boundaries. Most of the investigations of Zipf's law rely on the demarcations of cities imposed by census data, e.g., metropolitan areas and census-designated places. These demarcations or definitions (of cities) are criticized for being subjective or even arbitrary. Alternative solutions to defining cities are suggested, but they still rely on census data for their definitions. In this paper we demarcate urban agglomerations by clustering street nodes (including intersections and ends), forming what we call natural cities. Based on the demarcation, we found that Zipf's law holds remarkably well for all the natural cities (over 2-4 million in total) across the United States. There is little sensitivity for the holding with respect to the clustering resolution used for demarcating the natural cities. This is a big contrast to urban areas, as defined in the census data, which do not hold stable for Zipf's law. Keywords: Natural cities, power law, data-intensive geospatial computing, scaling of geographic space
Agent-based Simulation of Human Movement Shaped by the Underlying Street Structure
Bin Jiang,Tao Jia
Physics , 2009,
Abstract: Relying on random and purposive moving agents, we simulated human movement in large street networks. We found that aggregate flow, assigned to individual streets, is mainly shaped by the underlying street structure, and that human moving behavior (either random or purposive) has little effect on the aggregate flow. This finding implies that given a street network, the movement patterns generated by purposive walkers (mostly human beings) and by random walkers are the same. Based on the simulation and correlation analysis, we further found that the closeness centrality is not a good indicator for human movement, in contrast to a long standing view held by space syntax researchers. Instead we suggest that Google's PageRank, and its modified version - weighted PageRank, betweenness and degree centralities are all better indicators for predicting aggregate flow.
Measuring Urban Sprawl Based on Massive Street Nodes and the Novel Concept of Natural Cities
Tao Jia,Bin Jiang
Physics , 2010,
Abstract: In this paper, we develop a novel approach to measuring urban sprawl based on street nodes and naturally defined urban boundaries, both extracted from massive volunteered geographic information OpenStreetMap databases through some data-intensive computing processes. The street nodes are defined as street intersections and ends, while the naturally defined urban boundaries constitute what we call natural cities. We find that the street nodes are significantly correlated with population of cities. Based on this finding, we set street nodes as a proxy of population to measure urban sprawl. We further find that street nodes bear a significant linear relationship with city areal extents. In the plot with the x axis representing city areal extents, and the y axis street nodes, sprawling cities are located below the regression line. We verified the approach using urban areas and population from the US census, and then applied the approach to three European countries: France, Germany, and the United Kingdom for the categorization of natural cities into three classes: sprawling, compact, and normal. This categorization sets a uniform standard for cross comparing sprawling levels across an entire country. Keywords: Street networks, openstreetmap, volunteered geographic information, GIS
Exploring Human Mobility Patterns Based on Location Information of US Flights
Bin Jiang,Tao Jia
Computer Science , 2011,
Abstract: A range of early studies have been conducted to illustrate human mobility patterns using different tracking data, such as dollar notes, cell phones and taxicabs. Here, we explore human mobility patterns based on massive tracking data of US flights. Both topological and geometric properties are examined in detail. We found that topological properties, such as traffic volume (between airports) and degree of connectivity (of individual airports), including both in- and outdegrees, follow a power law distribution but not a geometric property like travel lengths. The travel lengths exhibit an exponential distribution rather than a power law with an exponential cutoff as previous studies illustrated. We further simulated human mobility on the established topologies of airports with various moving behaviors and found that the mobility patterns are mainly attributed to the underlying binary topology of airports and have little to do with other factors, such as moving behaviors and geometric distances. Apart from the above findings, this study adopts the head/tail division rule, which is regularity behind any heavy-tailed distribution for extracting individual airports. The adoption of this rule for data processing constitutes another major contribution of this paper. Keywords: scaling of geographic space, head/tail division rule, power law, geographic information, agent-based simulations
Knowledge in Communication Networks
Pavel Naumov,Jia Tao
Computer Science , 2015,
Abstract: The paper investigates epistemic properties of information flow under communication protocols with a given topological structure of the communication network. The main result is a sound and complete logical system that describes all such properties. The system consists of a variation of the multi-agent epistemic logic S5 extended by a new network-specific Gateway axiom.
On the structural properties of small-world networks with finite range of shortcut links
Tao Jia,Rahul V. Kulkarni
Computer Science , 2011,
Abstract: We explore a new variant of Small-World Networks (SWNs), in which an additional parameter ($r$) sets the length scale over which shortcuts are uniformly distributed. When $r=0$ we have an ordered network, whereas $r=1$ corresponds to the original SWN model. These short-range SWNs have a similar degree distribution and scaling properties as the original SWN model. We observe the small-world phenomenon for $r \ll 1$ indicating that global shortcuts are not necessary for the small-world effect. For short-range SWNs, the average path length changes nonmonotonically with system size, whereas for the original SWN model it increases monotonically. We propose an expression for the average path length for short-range SWNs based on numerical simulations and analytical approximations.
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