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Search Results: 1 - 10 of 164175 matches for " Cheng-Jun Wang "
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Bringing Reference Groups Back: Agent-based Modeling of the Spiral of Silence
Cheng-Jun Wang
Computer Science , 2013,
Abstract: The purpose of this study is threefold: first, to bring reference groups back into the framework of spiral of silence (SOS) by proposing an extended framework of dual opinion climate; second, to investigate the boundary conditions of SOS; third, to identify the characteristics of SOS in terms of spatial variation and temporal evolution. Modeling SOS with agent-based models, the findings suggest (1) there is no guarantee of SOS with reference groups being brought back; (2) Stable existence of SOS is contingent upon the comparative strength of mass media over reference groups; (3) SOS is size-dependent upon reference groups and the population; (4) the growth rate of SOS decreases over time. Thus, this research presents an extension of the SOS theory.
Study on the model of information transmission and controlling of the large-scale irrigated area based on information flow
基于信息流的大型灌区信息传递与控制模型研究

WANG Cheng-jun,
王成军

计算机应用 , 2005,
Abstract: For further investigate the essential element of information expressed of large-scale irrigation area and constructs the overall model of irrigation area system, the system engineering method was used to analyses the information source and information flow of irrigated area. By this method, the connection and state between each element transmit the relation in the system was described systematically and a model of Information transmission and controlling of the large-scale irrigated area was constructed. The application of this model to the irrigation are informationization shows that this model has offered the feasible quantization model for realization and accurate control of the information system of irrigated area.
A Combined Model of Global Cultivated Area Change and Prediction for Future: 1961–2020
Cheng-Jun Wang,Xi-Min Fei
ISRN Applied Mathematics , 2013, DOI: 10.1155/2013/125260
Abstract: As a basic condition for food safety, cultivated area fluctuates in recent years. So, it has important political and economical significance to understand the future change trend of global cultivated area. Based on historical data in the past 50 years, deterministic time series analysis model, random time series analysis model, and combined model were established by using time series analysis method. By comparison, the combined model has the highest fitting and prediction accuracy, and it is suitable for the prediction of global cultivated area change trend. The global cultivated area will rise slightly in fluctuation in the near future driven by a combination of deterministic factors and random factors. 1. Introduction Food is the first necessity for people, and it is the foundation for settling down. In recent years, food safety of various countries has already been the strategy of different countries in international exchange, so global food safety has always been the focus of all parties. Guarantee of food safety depends on two parts which are technological level and cultivated area, respectively. Cultivated land is the basis for food production [1], and grain output is closely related to cultivated area. As the carrier of food production, cultivated land is rare and irreplaceable [2]. Therefore, in-depth study on the evolution rule of global cultivated area and prediction for the future development trend of global cultivated area can predict the basic guarantee for global food safety. Besides, it can provide reference for making national cultivated land protection policy and food safety policy [3]. Global cultivated area has presented increased trend on the whole since the 1960s, as illustrated in Figure 1. The average annual increase of cultivated area from 1961 to 2011 is about 7,150,897 hectares (calculated according to data provided by the World Bank). However, in the process of increase, different forms are presented at different stages and there are 3 stages in general. The first stage is from 1961 to 1990 when the cultivated area increases stably and the average annual increase of cultivated area is 4,211,730 hectares. The second stage is from 1990 to 1993 when the cultivated area is adjusted greatly owing to statistical caliber change of some countries. The third stage is from 1993 till now when the global cultivated area fluctuates. It increases for 7 years and decreases for 9 years from 1993 to 2011. On the whole, the change of global cultivated area presents a certain trend, especially at the first stage when it rises significantly. But
The Hidden Geometry of Attention Diffusion
Cheng-Jun Wang,Lingfei Wu,Jiang Zhang,Marco Janssen
Physics , 2015,
Abstract: We propose a geometric model to quantify the dynamics of attention in online communities. Using clicks as a proxy of attention, we find that the diffusion of collective attention in Web forums and news sharing sites forms time-invariant "fields" whose density vary solely with distance from the center of the fields that represents the input of attention from the physical world. As time goes by, old information pieces are pushed farther from the center by new pieces, receive fewer and fewer clicks, and eventually become invisible in the virtual world. The discovered "attention fields" not only explain the fast decay of attention to information pieces, but also predict the accelerating growth of clicks against the active user population, which is a universal pattern relevant to the economics of scales of online interactions.
STAT3 or USF2 Contributes to HIF Target Gene Specificity
Matthew R. Pawlus, Liyi Wang, Aya Murakami, Guanhai Dai, Cheng-Jun Hu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072358
Abstract: The HIF1- and HIF2-mediated transcriptional responses play critical roles in solid tumor progression. Despite significant similarities, including their binding to promoters of both HIF1 and HIF2 target genes, HIF1 and HIF2 proteins activate unique subsets of target genes under hypoxia. The mechanism for HIF target gene specificity has remained unclear. Using siRNA or inhibitor, we previously reported that STAT3 or USF2 is specifically required for activation of endogenous HIF1 or HIF2 target genes. In this study, using reporter gene assays and chromatin immuno-precipitation, we find that STAT3 or USF2 exhibits specific binding to the promoters of HIF1 or HIF2 target genes respectively even when over-expressed. Functionally, HIF1α interacts with STAT3 to activate HIF1 target gene promoters in a HIF1α HLH/PAS and N-TAD dependent manner while HIF2α interacts with USF2 to activate HIF2 target gene promoters in a HIF2α N-TAD dependent manner. Physically, HIF1α HLH and PAS domains are required for its interaction with STAT3 while both N- and C-TADs of HIF2α are involved in physical interaction with USF2. Importantly, addition of functional USF2 binding sites into a HIF1 target gene promoter increases the basal activity of the promoter as well as its response to HIF2+USF2 activation while replacing HIF binding site with HBS from a HIF2 target gene does not change the specificity of the reporter gene. Importantly, RNA Pol II on HIF1 or HIF2 target genes is primarily associated with HIF1α or HIF2α in a STAT3 or USF2 dependent manner. Thus, we demonstrate here for the first time that HIF target gene specificity is achieved by HIF transcription partners that are required for HIF target gene activation, exhibit specific binding to the promoters of HIF1 or HIF2 target genes and selectively interact with HIF1α or HIF2α protein.
Residues and distribution character of organochlorine pesticides in stream sediments in southwestern suburb of Nanjing
南京市小河流表层沉积物中的有机氯农药残留及其分布现状

An Qiong,Dong Yuan-hua,Ge Cheng-jun,Wang Hui,
An Q
,Dong YH,Ge CJ,Wang H

环境科学 , 2006,
Abstract: Sediments and water samples were collected from different cross sections of 4 tributaries of Yangtze River in southwestern suburb of Nanjing city in spring 2004,and agricultural soil sample were collected also in those valleys.The residues and distribution of organochlorine pesticides in sediments from different streams were determined and the influence of soil character on organochlorine pesticides residues in sediments were studied.Result showed that accumulation of HCHs and DDTs occured significantly in the sediments and related to soil erosion.Residues of organochlorine pesticides in sediments may be influenced obviously by pH of agricultural soil in the valleys.In the alkaline soil,organic matters could be leached easily and entered the stream water and accumulated into sediments,resulting in accumulation of organochlorine pesticides adsorbed on soil organic matters in sediments.In the transfer process of materials from soil to water and sediment,constitutes of organochlorine pesticides in multiphase environmental medium were changed;usually those components easily leached from soils had higher residue levels in sediments.Meanwhile,sedimentation of soil in streams could reduce OCPs input to the Yangtze River.
A Proof Assistant for Interval Logics
区间逻辑的一个辅助证明工具

HU Cheng-jun,WANG Ji,CHEN Huo-wang,
胡成军
,王戟,陈火旺

软件学报 , 2000,
Abstract: DC/P (duration calculus prover) is a proof assistant for a family of interval logics. It adopts the Gentzen-style sequent calculus as its basic proof system. The techniques such as term rewriting and automatic decision procedure are integrated to automate many trivial proof steps. In this paper, the authors briefly describe the semantic encoding approach, and the sequent calculus, as well as the related implementation techniques of the DC/P.
Ranking spreaders by decomposing complex networks
An Zeng,Cheng-Jun Zhang
Physics , 2012, DOI: 10.1016/j.physleta.2013.02.039
Abstract: Ranking the nodes' ability for spreading in networks is a fundamental problem which relates to many real applications such as information and disease control. In the previous literatures, a network decomposition procedure called k-shell method has been shown to effectively identify the most influential spreaders. In this paper, we find that the k-shell method have some limitations when it is used to rank all the nodes in the network. We also find that these limitations are due to considering only the links between the remaining nodes (residual degree) while entirely ignoring all the links connecting to the removed nodes (exhausted degree) when decomposing the networks. Accordingly, we propose a mixed degree decomposition (MDD) procedure in which both the residual degree and the exhausted degree are considered. By simulating the epidemic process on the real networks, we show that the MDD method can outperform the k-shell and the degree methods in ranking spreaders. Finally, the influence of the network structure on the performance of the MDD method is discussed.
Behavior patterns of online users and the effect on information filtering
Cheng-Jun Zhang,An Zeng
Computer Science , 2011, DOI: 10.1016/j.physa.2011.09.038
Abstract: Understanding the structure and evolution of web-based user-object bipartite networks is an important task since they play a fundamental role in online information filtering. In this paper, we focus on investigating the patterns of online users' behavior and the effect on recommendation process. Empirical analysis on the e-commercial systems show that users have significant taste diversity and their interests for niche items highly overlap. Additionally, recommendation process are investigated on both the real networks and the reshuffled networks in which real users' behavior patterns can be gradually destroyed. Our results shows that the performance of personalized recommendation methods is strongly related to the real network structure. Detail study on each item shows that recommendation accuracy for hot items is almost maximum and quite robust to the reshuffling process. However, niche items cannot be accurately recommended after removing users' behavior patterns. Our work also is meaningful in practical sense since it reveals an effective direction to improve the accuracy and the robustness of the existing recommender systems.
管板组合结构等效力学模型
An Equivalent Mechanical Model for a Tube-Plate Composite Structure

王玲,董有恒,王成军,刘岩
WANG Ling
,DONG You-heng,WANG Cheng-jun,LIU Yan

- , 2017, DOI: 10.13718/j.cnki.xdzk.2017.08.026
Abstract: 通过将管板组合结构等效为正交各向异性板的方法,探讨该类结构的力学响应的计算方法.首先从平面问题本构方程出发,应用变形协调条件得到其等效材料参数,然后应用刚度分析法得到其等效厚度与等效密度,最后通过与3D有限元结果比较说明等效模型的正确性.
The computational method of the mechanical responses of the tube-plate composite structure is given by putting the composite structure to an equivalent orthotropic anisotropic plate. First, the equivalent material parameters are obtained by combining the constitutive equations of the plane problems and the deformation compatibility conditions. Then the equivalent thickness and density of the plate are obtained with stiffness analysis. Finally, the correctness of the equivalent model is verified by comparing the 3D-FEM results with those obtained by the present method
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